diff --git a/lib/jekyll/filters.rb b/lib/jekyll/filters.rb
index 67d74a02..b3ef7695 100644
--- a/lib/jekyll/filters.rb
+++ b/lib/jekyll/filters.rb
@@ -186,7 +186,7 @@ module Jekyll
     #
     # Returns the filtered array of objects
     def where(input, key, value)
-      return input unless input.class == Array
+      return input unless input.is_a?(Array)
       input.select { |object| object[key] == value }
     end