diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index bb56f4c..48056f3 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -384,7 +384,7 @@ module Liquid
       end
 
       def join(glue)
-        to_a.join(glue)
+        to_a.join(glue.to_s)
       end
 
       def concat(args)
diff --git a/test/integration/standard_filter_test.rb b/test/integration/standard_filter_test.rb
index fcbfd88..e607b76 100644
--- a/test/integration/standard_filter_test.rb
+++ b/test/integration/standard_filter_test.rb
@@ -170,6 +170,7 @@ class StandardFiltersTest < Minitest::Test
   def test_join
     assert_equal '1 2 3 4', @filters.join([1, 2, 3, 4])
     assert_equal '1 - 2 - 3 - 4', @filters.join([1, 2, 3, 4], ' - ')
+    assert_equal '1121314', @filters.join([1, 2, 3, 4], 1)
   end
 
   def test_sort