diff --git a/spec/support/adapters/mongo_mapper/connection.rb b/spec/support/adapters/mongo_mapper/connection.rb
index 2f817b2..f83289c 100644
--- a/spec/support/adapters/mongo_mapper/connection.rb
+++ b/spec/support/adapters/mongo_mapper/connection.rb
@@ -1,3 +1,12 @@
+# We need to require "active_support" first here because MongoMapper requires
+# "active_support/core_ext" without first requiring "active_support". On some
+# systems, this causes intermittent test suite failures.
+#
+# See: https://github.com/rails/rails/issues/14664
+# and: https://github.com/mongomapper/mongomapper/commit/64f9fc6
+#
+require "active_support"
+
 require "mongo_mapper"
 
 MongoMapper.connection = Mongo::Connection.new