diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 40e73ae77f..8f4ec5cb49 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Add Time#to_s(:iso8601) for easy conversion of times to the iso8601 format for easy Javascript date parsing.
+
+    *DHH*
+
 *   Improve `ActiveSupport::Cache::MemoryStore` cache size calculation.
     The memory used by a key/entry pair is calculated via `#cached_size`:
 
diff --git a/activesupport/lib/active_support/core_ext/time/conversions.rb b/activesupport/lib/active_support/core_ext/time/conversions.rb
index 48654eb1cc..a87455dedb 100644
--- a/activesupport/lib/active_support/core_ext/time/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/time/conversions.rb
@@ -16,7 +16,8 @@ class Time
     :rfc822       => lambda { |time|
       offset_format = time.formatted_offset(false)
       time.strftime("%a, %d %b %Y %H:%M:%S #{offset_format}")
-    }
+    },
+    :iso8601      => "%Y-%m-%dT%H:%M:%SZ"
   }
 
   # Converts to a formatted string. See DATE_FORMATS for builtin formats.
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index 8741f033b5..c9e9d5cbc4 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -503,6 +503,7 @@ class TimeExtCalculationsTest < ActiveSupport::TestCase
     assert_equal "20050221174430123456789",         time.to_s(:nsec)
     assert_equal "February 21, 2005 17:44",         time.to_s(:long)
     assert_equal "February 21st, 2005 17:44",       time.to_s(:long_ordinal)
+    assert_equal "2009-02-05T14:30:05Z", Time.local(2009, 2, 5, 14, 30, 5).to_s(:iso8601)
     with_env_tz "UTC" do
       assert_equal "Mon, 21 Feb 2005 17:44:30 +0000", time.to_s(:rfc822)
     end