diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index 0f4c914..d39211e 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -89,13 +89,22 @@ module Liquid
 
     def truncatewords(input, words = 15, truncate_string = "...")
       return if input.nil?
-      wordlist = input.to_s.split
-      words    = Utils.to_integer(words)
+      words = Utils.to_integer(words)
 
-      l = words - 1
-      l = 0 if l < 0
+      l = words
+      l = 1 if l <= 0
 
-      wordlist.length > l ? wordlist[0..l].join(" ").concat(truncate_string.to_s) : input
+      # Scan for non-space characters followed by one or more space characters
+      # `l` times.  Also ignore leading whitespace
+      str = input[/\A[ ]*(?:[^ ]*[ ]+){#{l}}/]
+
+      if str
+        str.strip!                # Remove trailing space
+        str.gsub!(/[ ]{2,}/, " ") # Shrink multiple spaces to one space
+        str.concat(truncate_string.to_s)
+      else
+        input
+      end
     end
 
     # Split input string into an array of substrings separated by given pattern.
diff --git a/test/integration/standard_filter_test.rb b/test/integration/standard_filter_test.rb
index 76ab462..69c57ab 100644
--- a/test/integration/standard_filter_test.rb
+++ b/test/integration/standard_filter_test.rb
@@ -168,6 +168,8 @@ class StandardFiltersTest < Minitest::Test
   def test_truncatewords
     assert_equal('one two three', @filters.truncatewords('one two three', 4))
     assert_equal('one two...', @filters.truncatewords('one two three', 2))
+    assert_equal('one two...', @filters.truncatewords('one     two three', 2))
+    assert_equal('one two...', @filters.truncatewords('   one     two three', 2))
     assert_equal('one two three', @filters.truncatewords('one two three'))
     assert_equal(
       'Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221;...',
@@ -175,6 +177,8 @@ class StandardFiltersTest < Minitest::Test
     )
     assert_equal("测试测试测试测试", @filters.truncatewords('测试测试测试测试', 5))
     assert_equal('one two1', @filters.truncatewords("one two three", 2, 1))
+    assert_equal('one1', @filters.truncatewords("one two three", 0, 1))
+    assert_equal('one1', @filters.truncatewords("one two three", -1, 1))
   end
 
   def test_strip_html