diff --git a/History.md b/History.md
index 69d4bd3..9083759 100644
--- a/History.md
+++ b/History.md
@@ -3,6 +3,7 @@
 ## 3.0.0 / not yet released / branch "master"
 
 * ...
+* Freeze lots of string literals for new Ruby 2.1 optimization, see #297 [Florian Weingarten, fw42]
 * Allow newlines in tags and variables, see #324 [Dylan Thacker-Smith, dylanahsmith]
 * Tag#parse is called after initialize, which now takes options instead of tokens as the 3rd argument. See #321 [Dylan Thacker-Smith, dylanahsmith]
 * Raise `Liquid::ArgumentError` instead of `::ArgumentError` when filter has wrong number of arguments #309 [Bogdan Gusiev, bogdan]
diff --git a/lib/liquid.rb b/lib/liquid.rb
index 3b35e56..484f8b6 100644
--- a/lib/liquid.rb
+++ b/lib/liquid.rb
@@ -21,9 +21,9 @@
 
 module Liquid
   FilterSeparator             = /\|/
-  ArgumentSeparator           = ','
-  FilterArgumentSeparator     = ':'
-  VariableAttributeSeparator  = '.'
+  ArgumentSeparator           = ','.freeze
+  FilterArgumentSeparator     = ':'.freeze
+  VariableAttributeSeparator  = '.'.freeze
   TagStart                    = /\{\%/
   TagEnd                      = /\%\}/
   VariableSignature           = /\(?[\w\-\.\[\]]\)?/
diff --git a/lib/liquid/block.rb b/lib/liquid/block.rb
index c53c5c5..a5118f9 100644
--- a/lib/liquid/block.rb
+++ b/lib/liquid/block.rb
@@ -41,14 +41,14 @@ module Liquid
               unknown_tag($1, $2, tokens)
             end
           else
-            raise SyntaxError.new(options[:locale].t("errors.syntax.tag_termination", :token => token, :tag_end => TagEnd.inspect))
+            raise SyntaxError.new(options[:locale].t("errors.syntax.tag_termination".freeze, :token => token, :tag_end => TagEnd.inspect))
           end
         when IsVariable
           new_var = create_variable(token)
           @nodelist << new_var
           @children << new_var
           @blank = false
-        when ''
+        when ''.freeze
           # pass
         else
           @nodelist << token
@@ -79,15 +79,15 @@ module Liquid
 
     def unknown_tag(tag, params, tokens)
       case tag
-      when 'else'
-        raise SyntaxError.new(options[:locale].t("errors.syntax.unexpected_else", 
+      when 'else'.freeze
+        raise SyntaxError.new(options[:locale].t("errors.syntax.unexpected_else".freeze,
                                                  :block_name => block_name))
-      when 'end'
-        raise SyntaxError.new(options[:locale].t("errors.syntax.invalid_delimiter", 
-                                                 :block_name => block_name, 
+      when 'end'.freeze
+        raise SyntaxError.new(options[:locale].t("errors.syntax.invalid_delimiter".freeze,
+                                                 :block_name => block_name,
                                                  :block_delimiter => block_delimiter))
       else
-        raise SyntaxError.new(options[:locale].t("errors.syntax.unknown_tag", :tag => tag))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.unknown_tag".freeze, :tag => tag))
       end
     end
 
@@ -103,7 +103,7 @@ module Liquid
       token.scan(ContentOfVariable) do |content|
         return Variable.new(content.first, @options)
       end
-      raise SyntaxError.new(options[:locale].t("errors.syntax.variable_termination", :token => token, :tag_end => VariableEnd.inspect))
+      raise SyntaxError.new(options[:locale].t("errors.syntax.variable_termination".freeze, :token => token, :tag_end => VariableEnd.inspect))
     end
 
     def render(context)
@@ -113,7 +113,7 @@ module Liquid
     protected
 
     def assert_missing_delimitation!
-      raise SyntaxError.new(options[:locale].t("errors.syntax.tag_never_closed", :block_name => block_name))
+      raise SyntaxError.new(options[:locale].t("errors.syntax.tag_never_closed".freeze, :block_name => block_name))
     end
 
     def render_all(list, context)
@@ -138,7 +138,7 @@ module Liquid
           context.increment_used_resources(:render_length_current, token_output)
           if context.resource_limits_reached?
             context.resource_limits[:reached] = true
-            raise MemoryError.new("Memory limits exceeded")
+            raise MemoryError.new("Memory limits exceeded".freeze)
           end
           unless token.is_a?(Block) && token.blank?
             output << token_output
diff --git a/lib/liquid/condition.rb b/lib/liquid/condition.rb
index ade7ac1..bf025d9 100644
--- a/lib/liquid/condition.rb
+++ b/lib/liquid/condition.rb
@@ -8,14 +8,14 @@ module Liquid
   #
   class Condition #:nodoc:
     @@operators = {
-      '==' => lambda { |cond, left, right|  cond.send(:equal_variables, left, right) },
-      '!=' => lambda { |cond, left, right| !cond.send(:equal_variables, left, right) },
-      '<>' => lambda { |cond, left, right| !cond.send(:equal_variables, left, right) },
-      '<'  => :<,
-      '>'  => :>,
-      '>=' => :>=,
-      '<=' => :<=,
-      'contains' => lambda { |cond, left, right| left && right ? left.include?(right) : false }
+      '=='.freeze => lambda { |cond, left, right|  cond.send(:equal_variables, left, right) },
+      '!='.freeze => lambda { |cond, left, right| !cond.send(:equal_variables, left, right) },
+      '<>'.freeze => lambda { |cond, left, right| !cond.send(:equal_variables, left, right) },
+      '<'.freeze  => :<,
+      '>'.freeze  => :>,
+      '>='.freeze => :>=,
+      '<='.freeze => :<=,
+      'contains'.freeze => lambda { |cond, left, right| left && right ? left.include?(right) : false }
     }
 
     def self.operators
@@ -61,7 +61,7 @@ module Liquid
     end
 
     def inspect
-      "#<Condition #{[@left, @operator, @right].compact.join(' ')}>"
+      "#<Condition #{[@left, @operator, @right].compact.join(' '.freeze)}>"
     end
 
     private
diff --git a/lib/liquid/context.rb b/lib/liquid/context.rb
index 1da66a9..0663bc5 100644
--- a/lib/liquid/context.rb
+++ b/lib/liquid/context.rb
@@ -103,7 +103,7 @@ module Liquid
     # Push new local scope on the stack. use <tt>Context#stack</tt> instead
     def push(new_scope={})
       @scopes.unshift(new_scope)
-      raise StackLevelError, "Nesting too deep" if @scopes.length > 100
+      raise StackLevelError, "Nesting too deep".freeze if @scopes.length > 100
     end
 
     # Merge a hash of variables in the current local scope
@@ -151,11 +151,11 @@ module Liquid
 
     private
       LITERALS = {
-        nil => nil, 'nil' => nil, 'null' => nil, '' => nil,
-        'true'  => true,
-        'false' => false,
-        'blank' => :blank?,
-        'empty' => :empty?
+        nil => nil, 'nil'.freeze => nil, 'null'.freeze => nil, ''.freeze => nil,
+        'true'.freeze  => true,
+        'false'.freeze => false,
+        'blank'.freeze => :blank?,
+        'empty'.freeze => :empty?
       }
 
       # Look up variable, either resolve directly after considering the name. We can directly handle
@@ -244,7 +244,7 @@ module Liquid
               # Some special cases. If the part wasn't in square brackets and
               # no key with the same name was found we interpret following calls
               # as commands and call them on the current object
-            elsif !part_resolved and object.respond_to?(part) and ['size', 'first', 'last'].include?(part)
+            elsif !part_resolved and object.respond_to?(part) and ['size'.freeze, 'first'.freeze, 'last'.freeze].include?(part)
 
               object = object.send(part.intern).to_liquid
 
diff --git a/lib/liquid/file_system.rb b/lib/liquid/file_system.rb
index 3fb823a..f95f644 100644
--- a/lib/liquid/file_system.rb
+++ b/lib/liquid/file_system.rb
@@ -44,7 +44,7 @@ module Liquid
   class LocalFileSystem
     attr_accessor :root
 
-    def initialize(root, pattern = "_%s.liquid")
+    def initialize(root, pattern = "_%s.liquid".freeze)
       @root = root
       @pattern = pattern
     end
@@ -59,7 +59,7 @@ module Liquid
     def full_path(template_path)
       raise FileSystemError, "Illegal template name '#{template_path}'" unless template_path =~ /\A[^.\/][a-zA-Z0-9_\/]+\z/
 
-      full_path = if template_path.include?('/')
+      full_path = if template_path.include?('/'.freeze)
         File.join(root, File.dirname(template_path), @pattern % File.basename(template_path))
       else
         File.join(root, @pattern % template_path)
diff --git a/lib/liquid/i18n.rb b/lib/liquid/i18n.rb
index 205b740..3a59b1f 100644
--- a/lib/liquid/i18n.rb
+++ b/lib/liquid/i18n.rb
@@ -6,7 +6,7 @@ module Liquid
 
     class TranslationError < StandardError
     end
-    
+
     attr_reader :path
 
     def initialize(path = DEFAULT_LOCALE)
@@ -31,7 +31,7 @@ module Liquid
     end
 
     def deep_fetch_translation(name)
-      name.split('.').reduce(locale) do |level, cur|
+      name.split('.'.freeze).reduce(locale) do |level, cur|
         level[cur] or raise TranslationError, "Translation for #{name} does not exist in locale #{path}"
       end
     end
diff --git a/lib/liquid/interrupts.rb b/lib/liquid/interrupts.rb
index d6bf61e..6ff01ac 100644
--- a/lib/liquid/interrupts.rb
+++ b/lib/liquid/interrupts.rb
@@ -5,7 +5,7 @@ module Liquid
     attr_reader :message
 
     def initialize(message=nil)
-      @message = message || "interrupt"
+      @message = message || "interrupt".freeze
     end
   end
 
diff --git a/lib/liquid/lexer.rb b/lib/liquid/lexer.rb
index 47a9fc4..0ecd8e0 100644
--- a/lib/liquid/lexer.rb
+++ b/lib/liquid/lexer.rb
@@ -2,14 +2,14 @@ require "strscan"
 module Liquid
   class Lexer
     SPECIALS = {
-      '|' => :pipe,
-      '.' => :dot,
-      ':' => :colon,
-      ',' => :comma,
-      '[' => :open_square,
-      ']' => :close_square,
-      '(' => :open_round,
-      ')' => :close_round
+      '|'.freeze => :pipe,
+      '.'.freeze => :dot,
+      ':'.freeze => :colon,
+      ','.freeze => :comma,
+      '['.freeze => :open_square,
+      ']'.freeze => :close_square,
+      '('.freeze => :open_round,
+      ')'.freeze => :close_round
     }
     IDENTIFIER = /[\w\-?!]+/
     SINGLE_STRING_LITERAL = /'[^\']*'/
diff --git a/lib/liquid/parser.rb b/lib/liquid/parser.rb
index 26f235f..d2006f3 100644
--- a/lib/liquid/parser.rb
+++ b/lib/liquid/parser.rb
@@ -66,10 +66,11 @@ module Liquid
       str = ""
       # might be a keyword argument (identifier: expression)
       if look(:id) && look(:colon, 1)
-        str << consume << consume << ' '
+        str << consume << consume << ' '.freeze
       end
 
       str << expression
+      str
     end
 
     def variable_signature
diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index 6163b4c..3cc3cc8 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -4,12 +4,17 @@ require 'bigdecimal'
 module Liquid
 
   module StandardFilters
-    HTML_ESCAPE = { '&' => '&amp;',  '>' => '&gt;',   '<' => '&lt;', '"' => '&quot;', "'" => '&#39;' }
+    HTML_ESCAPE = {
+      '&'.freeze => '&amp;'.freeze,
+      '>'.freeze => '&gt;'.freeze,
+      '<'.freeze => '&lt;'.freeze,
+      '"'.freeze => '&quot;'.freeze,
+      "'".freeze => '&#39;'.freeze
+    }
     HTML_ESCAPE_ONCE_REGEXP = /["><']|&(?!([a-zA-Z]+|(#\d+));)/
 
     # Return the size of an array or of an string
     def size(input)
-
       input.respond_to?(:size) ? input.size : 0
     end
 
@@ -39,19 +44,19 @@ module Liquid
     alias_method :h, :escape
 
     # Truncate a string down to x characters
-    def truncate(input, length = 50, truncate_string = "...")
+    def truncate(input, length = 50, truncate_string = "...".freeze)
       if input.nil? then return end
       l = length.to_i - truncate_string.length
       l = 0 if l < 0
       input.length > length.to_i ? input[0...l] + truncate_string : input
     end
 
-    def truncatewords(input, words = 15, truncate_string = "...")
+    def truncatewords(input, words = 15, truncate_string = "...".freeze)
       if input.nil? then return end
       wordlist = input.to_s.split
       l = words.to_i - 1
       l = 0 if l < 0
-      wordlist.length > l ? wordlist[0..l].join(" ") + truncate_string : input
+      wordlist.length > l ? wordlist[0..l].join(" ".freeze) + truncate_string : input
     end
 
     # Split input string into an array of substrings separated by given pattern.
@@ -76,16 +81,17 @@ module Liquid
     end
 
     def strip_html(input)
-      input.to_s.gsub(/<script.*?<\/script>/m, '').gsub(/<!--.*?-->/m, '').gsub(/<style.*?<\/style>/m, '').gsub(/<.*?>/m, '')
+      empty = ''.freeze
+      input.to_s.gsub(/<script.*?<\/script>/m, empty).gsub(/<!--.*?-->/m, empty).gsub(/<style.*?<\/style>/m, empty).gsub(/<.*?>/m, empty)
     end
 
     # Remove all newlines from the string
     def strip_newlines(input)
-      input.to_s.gsub(/\r?\n/, '')
+      input.to_s.gsub(/\r?\n/, ''.freeze)
     end
 
     # Join elements of the array with certain character between them
-    def join(input, glue = ' ')
+    def join(input, glue = ' '.freeze)
       [input].flatten.join(glue)
     end
 
@@ -95,7 +101,7 @@ module Liquid
       ary = flatten_if_necessary(input)
       if property.nil?
         ary.sort
-      elsif ary.first.respond_to?('[]') and !ary.first[property].nil?
+      elsif ary.first.respond_to?('[]'.freeze) and !ary.first[property].nil?
         ary.sort {|a,b| a[property] <=> b[property] }
       elsif ary.first.respond_to?(property)
         ary.sort {|a,b| a.send(property) <=> b.send(property) }
@@ -113,7 +119,7 @@ module Liquid
       flatten_if_necessary(input).map do |e|
         e = e.call if e.is_a?(Proc)
 
-        if property == "to_liquid"
+        if property == "to_liquid".freeze
           e
         elsif e.respond_to?(:[])
           e[property]
@@ -122,23 +128,23 @@ module Liquid
     end
 
     # Replace occurrences of a string with another
-    def replace(input, string, replacement = '')
+    def replace(input, string, replacement = ''.freeze)
       input.to_s.gsub(string, replacement.to_s)
     end
 
     # Replace the first occurrences of a string with another
-    def replace_first(input, string, replacement = '')
+    def replace_first(input, string, replacement = ''.freeze)
       input.to_s.sub(string, replacement.to_s)
     end
 
     # remove a substring
     def remove(input, string)
-      input.to_s.gsub(string, '')
+      input.to_s.gsub(string, ''.freeze)
     end
 
     # remove the first occurrences of a substring
     def remove_first(input, string)
-      input.to_s.sub(string, '')
+      input.to_s.sub(string, ''.freeze)
     end
 
     # add one string to another
@@ -153,7 +159,7 @@ module Liquid
 
     # Add <br /> tags in front of all newlines in input string
     def newline_to_br(input)
-      input.to_s.gsub(/\n/, "<br />\n")
+      input.to_s.gsub(/\n/, "<br />\n".freeze)
     end
 
     # Reformat a date
@@ -196,7 +202,7 @@ module Liquid
 
       date = if input.is_a?(String)
         case input.downcase
-        when 'now', 'today'
+        when 'now'.freeze, 'today'.freeze
           Time.now
         else
           Time.parse(input)
@@ -256,7 +262,7 @@ module Liquid
       apply_operation(input, operand, :%)
     end
 
-    def default(input, default_value = "")
+    def default(input, default_value = "".freeze)
       is_blank = input.respond_to?(:empty?) ? input.empty? : !input
       is_blank ? default_value : input
     end
diff --git a/lib/liquid/tag.rb b/lib/liquid/tag.rb
index 2daf084..3df1045 100644
--- a/lib/liquid/tag.rb
+++ b/lib/liquid/tag.rb
@@ -27,7 +27,7 @@ module Liquid
     end
 
     def render(context)
-      ''
+      ''.freeze
     end
 
     def blank?
diff --git a/lib/liquid/tags/assign.rb b/lib/liquid/tags/assign.rb
index 75301b1..fa852a0 100644
--- a/lib/liquid/tags/assign.rb
+++ b/lib/liquid/tags/assign.rb
@@ -17,7 +17,7 @@ module Liquid
         @to = $1
         @from = Variable.new($2)
       else
-        raise SyntaxError.new options[:locale].t("errors.syntax.assign")
+        raise SyntaxError.new options[:locale].t("errors.syntax.assign".freeze)
       end
     end
 
@@ -25,7 +25,7 @@ module Liquid
       val = @from.render(context)
       context.scopes.last[@to] = val
       context.increment_used_resources(:assign_score_current, val)
-      ''
+      ''.freeze
     end
 
     def blank?
@@ -33,5 +33,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('assign', Assign)
+  Template.register_tag('assign'.freeze, Assign)
 end
diff --git a/lib/liquid/tags/break.rb b/lib/liquid/tags/break.rb
index 0626338..411a3b1 100644
--- a/lib/liquid/tags/break.rb
+++ b/lib/liquid/tags/break.rb
@@ -17,5 +17,5 @@ module Liquid
 
   end
 
-  Template.register_tag('break', Break)
+  Template.register_tag('break'.freeze, Break)
 end
diff --git a/lib/liquid/tags/capture.rb b/lib/liquid/tags/capture.rb
index 9acb22b..4bcd118 100644
--- a/lib/liquid/tags/capture.rb
+++ b/lib/liquid/tags/capture.rb
@@ -27,7 +27,7 @@ module Liquid
       output = super
       context.scopes.last[@to] = output
       context.increment_used_resources(:assign_score_current, output)
-      ''
+      ''.freeze
     end
 
     def blank?
@@ -35,5 +35,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('capture', Capture)
+  Template.register_tag('capture'.freeze, Capture)
 end
diff --git a/lib/liquid/tags/case.rb b/lib/liquid/tags/case.rb
index c63548e..1cc48d8 100644
--- a/lib/liquid/tags/case.rb
+++ b/lib/liquid/tags/case.rb
@@ -10,7 +10,7 @@ module Liquid
       if markup =~ Syntax
         @left = $1
       else
-        raise SyntaxError.new(options[:locale].t("errors.syntax.case"))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.case".freeze))
       end
     end
 
@@ -21,9 +21,9 @@ module Liquid
     def unknown_tag(tag, markup, tokens)
       @nodelist = []
       case tag
-      when 'when'
+      when 'when'.freeze
         record_when_condition(markup)
-      when 'else'
+      when 'else'.freeze
         record_else_condition(markup)
       else
         super
@@ -53,12 +53,12 @@ module Liquid
       while markup
         # Create a new nodelist and assign it to the new block
         if not markup =~ WhenSyntax
-          raise SyntaxError.new(options[:locale].t("errors.syntax.case_invalid_when"))
+          raise SyntaxError.new(options[:locale].t("errors.syntax.case_invalid_when".freeze))
         end
 
         markup = $2
 
-        block = Condition.new(@left, '==', $1)
+        block = Condition.new(@left, '=='.freeze, $1)
         block.attach(@nodelist)
         @blocks.push(block)
       end
@@ -66,7 +66,7 @@ module Liquid
 
     def record_else_condition(markup)
       if not markup.strip.empty?
-        raise SyntaxError.new(options[:locale].t("errors.syntax.case_invalid_else"))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.case_invalid_else".freeze))
       end
 
       block = ElseCondition.new
@@ -75,5 +75,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('case', Case)
+  Template.register_tag('case'.freeze, Case)
 end
diff --git a/lib/liquid/tags/comment.rb b/lib/liquid/tags/comment.rb
index 099310e..3e6bb69 100644
--- a/lib/liquid/tags/comment.rb
+++ b/lib/liquid/tags/comment.rb
@@ -1,7 +1,7 @@
 module Liquid
   class Comment < Block
     def render(context)
-      ''
+      ''.freeze
     end
 
     def unknown_tag(tag, markup, tokens)
@@ -12,5 +12,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('comment', Comment)
+  Template.register_tag('comment'.freeze, Comment)
 end
diff --git a/lib/liquid/tags/continue.rb b/lib/liquid/tags/continue.rb
index 0512a7d..9c81ec2 100644
--- a/lib/liquid/tags/continue.rb
+++ b/lib/liquid/tags/continue.rb
@@ -1,5 +1,4 @@
 module Liquid
-
   # Continue tag to be used to break out of a for loop.
   #
   # == Basic Usage:
@@ -10,12 +9,10 @@ module Liquid
   #    {% endfor %}
   #
   class Continue < Tag
-
     def interrupt
       ContinueInterrupt.new
     end
-
   end
 
-  Template.register_tag('continue', Continue)
+  Template.register_tag('continue'.freeze, Continue)
 end
diff --git a/lib/liquid/tags/cycle.rb b/lib/liquid/tags/cycle.rb
index c86f8a1..c3c7d87 100644
--- a/lib/liquid/tags/cycle.rb
+++ b/lib/liquid/tags/cycle.rb
@@ -25,7 +25,7 @@ module Liquid
         @variables = variables_from_string(markup)
         @name = "'#{@variables.to_s}'"
       else
-        raise SyntaxError.new(options[:locale].t("errors.syntax.cycle"))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.cycle".freeze))
       end
     end
 
diff --git a/lib/liquid/tags/decrement.rb b/lib/liquid/tags/decrement.rb
index e9b6606..d604750 100644
--- a/lib/liquid/tags/decrement.rb
+++ b/lib/liquid/tags/decrement.rb
@@ -34,5 +34,5 @@ module Liquid
     private
   end
 
-  Template.register_tag('decrement', Decrement)
+  Template.register_tag('decrement'.freeze, Decrement)
 end
diff --git a/lib/liquid/tags/for.rb b/lib/liquid/tags/for.rb
index 3cd9e97..6d29b64 100644
--- a/lib/liquid/tags/for.rb
+++ b/lib/liquid/tags/for.rb
@@ -61,7 +61,7 @@ module Liquid
     end
 
     def unknown_tag(tag, markup, tokens)
-      return super unless tag == 'else'
+      return super unless tag == 'else'.freeze
       @nodelist = @else_block = []
     end
 
@@ -74,13 +74,13 @@ module Liquid
       # Maintains Ruby 1.8.7 String#each behaviour on 1.9
       return render_else(context) unless iterable?(collection)
 
-      from = if @attributes['offset'] == 'continue'
+      from = if @attributes['offset'.freeze] == 'continue'.freeze
         context.registers[:for][@name].to_i
       else
-        context[@attributes['offset']].to_i
+        context[@attributes['offset'.freeze]].to_i
       end
 
-      limit = context[@attributes['limit']]
+      limit = context[@attributes['limit'.freeze]]
       to    = limit ? limit.to_i + from : nil
 
       segment = Utils.slice_collection(collection, from, to)
@@ -99,15 +99,16 @@ module Liquid
       context.stack do
         segment.each_with_index do |item, index|
           context[@variable_name] = item
-          context['forloop'] = {
-            'name'    => @name,
-            'length'  => length,
-            'index'   => index + 1,
-            'index0'  => index,
-            'rindex'  => length - index,
-            'rindex0' => length - index - 1,
-            'first'   => (index == 0),
-          'last'    => (index == length - 1) }
+          context['forloop'.freeze] = {
+            'name'.freeze    => @name,
+            'length'.freeze  => length,
+            'index'.freeze   => index + 1,
+            'index0'.freeze  => index,
+            'rindex'.freeze  => length - index,
+            'rindex0'.freeze => length - index - 1,
+            'first'.freeze   => (index == 0),
+            'last'.freeze    => (index == length - 1)
+          }
 
           result << render_all(@for_block, context)
 
@@ -135,22 +136,22 @@ module Liquid
           @attributes[key] = value
         end
       else
-        raise SyntaxError.new(options[:locale].t("errors.syntax.for"))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.for".freeze))
       end
     end
 
     def strict_parse(markup)
       p = Parser.new(markup)
       @variable_name = p.consume(:id)
-      raise SyntaxError.new(options[:locale].t("errors.syntax.for_invalid_in"))  unless p.id?('in')
+      raise SyntaxError.new(options[:locale].t("errors.syntax.for_invalid_in".freeze))  unless p.id?('in'.freeze)
       @collection_name = p.expression
       @name = "#{@variable_name}-#{@collection_name}"
-      @reversed = p.id?('reversed')
+      @reversed = p.id?('reversed'.freeze)
 
       @attributes = {}
       while p.look(:id) && p.look(:colon, 1)
-        unless attribute = p.id?('limit') || p.id?('offset')
-          raise SyntaxError.new(options[:locale].t("errors.syntax.for_invalid_attribute"))
+        unless attribute = p.id?('limit'.freeze) || p.id?('offset'.freeze)
+          raise SyntaxError.new(options[:locale].t("errors.syntax.for_invalid_attribute".freeze))
         end
         p.consume
         val = p.expression
@@ -161,14 +162,14 @@ module Liquid
 
     private
 
-      def render_else(context)
-        return @else_block ? [render_all(@else_block, context)] : ''
-      end
+    def render_else(context)
+      return @else_block ? [render_all(@else_block, context)] : ''.freeze
+    end
 
-      def iterable?(collection)
-        collection.respond_to?(:each) || Utils.non_blank_string?(collection)
-      end
+    def iterable?(collection)
+      collection.respond_to?(:each) || Utils.non_blank_string?(collection)
+    end
   end
 
-  Template.register_tag('for', For)
+  Template.register_tag('for'.freeze, For)
 end
diff --git a/lib/liquid/tags/if.rb b/lib/liquid/tags/if.rb
index ad48bb5..60bd634 100644
--- a/lib/liquid/tags/if.rb
+++ b/lib/liquid/tags/if.rb
@@ -17,7 +17,7 @@ module Liquid
     def initialize(tag_name, markup, options)
       super
       @blocks = []
-      push_block('if', markup)
+      push_block('if'.freeze, markup)
     end
 
     def nodelist
@@ -25,7 +25,7 @@ module Liquid
     end
 
     def unknown_tag(tag, markup, tokens)
-      if ['elsif', 'else'].include?(tag)
+      if ['elsif'.freeze, 'else'.freeze].include?(tag)
         push_block(tag, markup)
       else
         super
@@ -39,14 +39,14 @@ module Liquid
             return render_all(block.attachment, context)
           end
         end
-        ''
+        ''.freeze
       end
     end
 
     private
 
       def push_block(tag, markup)
-        block = if tag == 'else'
+        block = if tag == 'else'.freeze
           ElseCondition.new
         else
           parse_with_selected_parser(markup)
@@ -58,17 +58,17 @@ module Liquid
 
       def lax_parse(markup)
         expressions = markup.scan(ExpressionsAndOperators).reverse
-        raise(SyntaxError.new(options[:locale].t("errors.syntax.if"))) unless expressions.shift =~ Syntax
+        raise(SyntaxError.new(options[:locale].t("errors.syntax.if".freeze))) unless expressions.shift =~ Syntax
 
         condition = Condition.new($1, $2, $3)
 
         while not expressions.empty?
           operator = (expressions.shift).to_s.strip
 
-          raise(SyntaxError.new(options[:locale].t("errors.syntax.if"))) unless expressions.shift.to_s =~ Syntax
+          raise(SyntaxError.new(options[:locale].t("errors.syntax.if".freeze))) unless expressions.shift.to_s =~ Syntax
 
           new_condition = Condition.new($1, $2, $3)
-          raise(SyntaxError.new(options[:locale].t("errors.syntax.if"))) unless BOOLEAN_OPERATORS.include?(operator)
+          raise(SyntaxError.new(options[:locale].t("errors.syntax.if".freeze))) unless BOOLEAN_OPERATORS.include?(operator)
           new_condition.send(operator, condition)
           condition = new_condition
         end
@@ -81,7 +81,7 @@ module Liquid
 
         condition = parse_comparison(p)
 
-        while op = (p.id?('and') || p.id?('or'))
+        while op = (p.id?('and'.freeze) || p.id?('or'.freeze))
           new_cond = parse_comparison(p)
           new_cond.send(op, condition)
           condition = new_cond
@@ -102,5 +102,5 @@ module Liquid
       end
   end
 
-  Template.register_tag('if', If)
+  Template.register_tag('if'.freeze, If)
 end
diff --git a/lib/liquid/tags/ifchanged.rb b/lib/liquid/tags/ifchanged.rb
index c18a5c5..03a9fb0 100644
--- a/lib/liquid/tags/ifchanged.rb
+++ b/lib/liquid/tags/ifchanged.rb
@@ -10,11 +10,11 @@ module Liquid
           context.registers[:ifchanged] = output
           output
         else
-          ''
+          ''.freeze
         end
       end
     end
   end
 
-  Template.register_tag('ifchanged', Ifchanged)
+  Template.register_tag('ifchanged'.freeze, Ifchanged)
 end
diff --git a/lib/liquid/tags/include.rb b/lib/liquid/tags/include.rb
index 34b2b0b..d831932 100644
--- a/lib/liquid/tags/include.rb
+++ b/lib/liquid/tags/include.rb
@@ -31,7 +31,7 @@ module Liquid
         end
 
       else
-        raise SyntaxError.new(options[:locale].t("errors.syntax.include"))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.include".freeze))
       end
     end
 
@@ -51,7 +51,7 @@ module Liquid
           context[key] = context[value]
         end
 
-        context_variable_name = @template_name[1..-2].split('/').last
+        context_variable_name = @template_name[1..-2].split('/'.freeze).last
         if variable.is_a?(Array)
           variable.collect do |var|
             context[context_variable_name] = var
@@ -94,5 +94,5 @@ module Liquid
       end
   end
 
-  Template.register_tag('include', Include)
+  Template.register_tag('include'.freeze, Include)
 end
diff --git a/lib/liquid/tags/increment.rb b/lib/liquid/tags/increment.rb
index 251bd77..4592d1c 100644
--- a/lib/liquid/tags/increment.rb
+++ b/lib/liquid/tags/increment.rb
@@ -31,5 +31,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('increment', Increment)
+  Template.register_tag('increment'.freeze, Increment)
 end
diff --git a/lib/liquid/tags/raw.rb b/lib/liquid/tags/raw.rb
index eafe6d3..0980ee1 100644
--- a/lib/liquid/tags/raw.rb
+++ b/lib/liquid/tags/raw.rb
@@ -7,7 +7,7 @@ module Liquid
       @nodelist.clear
       while token = tokens.shift
         if token =~ FullTokenPossiblyInvalid
-          @nodelist << $1 if $1 != ""
+          @nodelist << $1 if $1 != "".freeze
           if block_delimiter == $2
             end_tag
             return
@@ -18,5 +18,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('raw', Raw)
+  Template.register_tag('raw'.freeze, Raw)
 end
diff --git a/lib/liquid/tags/table_row.rb b/lib/liquid/tags/table_row.rb
index 771042d..25457a3 100644
--- a/lib/liquid/tags/table_row.rb
+++ b/lib/liquid/tags/table_row.rb
@@ -12,21 +12,21 @@ module Liquid
           @attributes[key] = value
         end
       else
-        raise SyntaxError.new(options[:locale].t("errors.syntax.table_row"))
+        raise SyntaxError.new(options[:locale].t("errors.syntax.table_row".freeze))
       end
     end
 
     def render(context)
-      collection = context[@collection_name] or return ''
+      collection = context[@collection_name] or return ''.freeze
 
-      from = @attributes['offset'] ? context[@attributes['offset']].to_i : 0
-      to = @attributes['limit'] ? from + context[@attributes['limit']].to_i : nil
+      from = @attributes['offset'.freeze] ? context[@attributes['offset'.freeze]].to_i : 0
+      to = @attributes['limit'.freeze] ? from + context[@attributes['limit'.freeze]].to_i : nil
 
       collection = Utils.slice_collection(collection, from, to)
 
       length = collection.length
 
-      cols = context[@attributes['cols']].to_i
+      cols = context[@attributes['cols'.freeze]].to_i
 
       row = 1
       col = 0
@@ -36,19 +36,19 @@ module Liquid
 
         collection.each_with_index do |item, index|
           context[@variable_name] = item
-          context['tablerowloop'] = {
-            'length'  => length,
-            'index'   => index + 1,
-            'index0'  => index,
-            'col'     => col + 1,
-            'col0'    => col,
-            'index0'  => index,
-            'rindex'  => length - index,
-            'rindex0' => length - index - 1,
-            'first'   => (index == 0),
-            'last'    => (index == length - 1),
-            'col_first' => (col == 0),
-            'col_last'  => (col == cols - 1)
+          context['tablerowloop'.freeze] = {
+            'length'.freeze    => length,
+            'index'.freeze     => index + 1,
+            'index0'.freeze    => index,
+            'col'.freeze       => col + 1,
+            'col0'.freeze      => col,
+            'index0'.freeze    => index,
+            'rindex'.freeze    => length - index,
+            'rindex0'.freeze   => length - index - 1,
+            'first'.freeze     => (index == 0),
+            'last'.freeze      => (index == length - 1),
+            'col_first'.freeze => (col == 0),
+            'col_last'.freeze  => (col == cols - 1)
           }
 
 
@@ -69,5 +69,5 @@ module Liquid
     end
   end
 
-  Template.register_tag('tablerow', TableRow)
+  Template.register_tag('tablerow'.freeze, TableRow)
 end
diff --git a/lib/liquid/tags/unless.rb b/lib/liquid/tags/unless.rb
index e561481..eb8a731 100644
--- a/lib/liquid/tags/unless.rb
+++ b/lib/liquid/tags/unless.rb
@@ -1,7 +1,6 @@
 require File.dirname(__FILE__) + '/if'
 
 module Liquid
-
   # Unless is a conditional just like 'if' but works on the inverse logic.
   #
   #   {% unless x < 0 %} x is greater than zero {% end %}
@@ -23,11 +22,10 @@ module Liquid
           end
         end
 
-        ''
+        ''.freeze
       end
     end
   end
 
-
-  Template.register_tag('unless', Unless)
+  Template.register_tag('unless'.freeze, Unless)
 end
diff --git a/lib/liquid/template.rb b/lib/liquid/template.rb
index 4ca7961..13748d4 100644
--- a/lib/liquid/template.rb
+++ b/lib/liquid/template.rb
@@ -110,7 +110,7 @@ module Liquid
     #    filters and tags and might be useful to integrate liquid more with its host application
     #
     def render(*args)
-      return '' if @root.nil?
+      return ''.freeze if @root.nil?
 
       context = case args.first
       when Liquid::Context
diff --git a/lib/liquid/utils.rb b/lib/liquid/utils.rb
index cb96524..cfa675a 100644
--- a/lib/liquid/utils.rb
+++ b/lib/liquid/utils.rb
@@ -10,7 +10,7 @@ module Liquid
     end
 
     def self.non_blank_string?(collection)
-      collection.is_a?(String) && collection != ''
+      collection.is_a?(String) && collection != ''.freeze
     end
 
     def self.slice_collection_using_each(collection, from, to)
diff --git a/lib/liquid/variable.rb b/lib/liquid/variable.rb
index 3992d2a..9a9e387 100644
--- a/lib/liquid/variable.rb
+++ b/lib/liquid/variable.rb
@@ -19,7 +19,6 @@ module Liquid
       @markup  = markup
       @name    = nil
       @options = options || {}
-      
 
       case @options[:error_mode] || Template.error_mode
       when :strict then strict_parse(markup)
@@ -63,7 +62,7 @@ module Liquid
       @filters = []
       p = Parser.new(markup)
       # Could be just filters with no input
-      @name = p.look(:pipe) ? '' : p.expression
+      @name = p.look(:pipe) ? ''.freeze : p.expression
       while p.consume?(:pipe)
         filtername = p.consume(:id)
         filterargs = p.consume?(:colon) ? parse_filterargs(p) : []
@@ -86,7 +85,7 @@ module Liquid
     end
 
     def render(context)
-      return '' if @name.nil?
+      return ''.freeze if @name.nil?
       @filters.inject(context[@name]) do |output, filter|
         filterargs = []
         keyword_args = {}
diff --git a/lib/liquid/version.rb b/lib/liquid/version.rb
index d27c6d3..879cd12 100644
--- a/lib/liquid/version.rb
+++ b/lib/liquid/version.rb
@@ -1,4 +1,4 @@
 # encoding: utf-8
 module Liquid
-  VERSION = "3.0.0"
+  VERSION = "3.0.0".freeze
 end