diff --git a/ilios.gemspec b/ilios.gemspec
index 65fab91..00808aa 100644
--- a/ilios.gemspec
+++ b/ilios.gemspec
@@ -34,5 +34,5 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
   spec.extensions << 'ext/ilios/extconf.rb'
 
-  spec.add_runtime_dependency('mini_portile2', '~> 2.8')
+  spec.add_dependency('mini_portile2', '~> 2.8')
 end