diff --git a/activeresource.gemspec b/activeresource.gemspec
index 26b8aaac04..370bcff77d 100644
--- a/activeresource.gemspec
+++ b/activeresource.gemspec
@@ -29,4 +29,5 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency("rake")
   s.add_development_dependency("mocha", ">= 0.13.0")
+  s.add_development_dependency("rexml")
 end