diff --git a/railties/lib/rails/plugin/locator.rb b/railties/lib/rails/plugin/locator.rb
index 6e6d2201a1..fd7de4ee28 100644
--- a/railties/lib/rails/plugin/locator.rb
+++ b/railties/lib/rails/plugin/locator.rb
@@ -78,7 +78,8 @@ module Rails
     # a <tt>rails/init.rb</tt> file.
     class GemLocator < Locator
       def plugins
-        specs = Gem.loaded_specs.values.select do |spec|
+        specs = initializer.configuration.gems.map(&:specification)
+        specs + Gem.loaded_specs.values.select do |spec|
           spec.loaded_from && # prune stubs
             File.exist?(File.join(spec.full_gem_path, "rails", "init.rb"))
         end