diff --git a/rubocop-rake.gemspec b/rubocop-rake.gemspec
index df917b1..7b048c6 100644
--- a/rubocop-rake.gemspec
+++ b/rubocop-rake.gemspec
@@ -31,5 +31,5 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_runtime_dependency 'rubocop', '~> 1.0'
+  spec.add_dependency 'rubocop', '~> 1.0'
 end