diff --git a/recursive-open-struct.gemspec b/recursive-open-struct.gemspec
index 06c99e9..f51603b 100644
--- a/recursive-open-struct.gemspec
+++ b/recursive-open-struct.gemspec
@@ -40,5 +40,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency('rdoc', [">= 0"])
   s.add_development_dependency('rspec', "~> 3.2")
   s.add_development_dependency('simplecov', [">= 0"])
+
+  s.add_dependency('ostruct')
 end