diff --git a/dev-ruby/thor/thor-1.5.0.ebuild b/dev-ruby/thor/thor-1.5.0.ebuild
index 3f9d3c8513f5a..8b5e7e5a904d3 100644
--- a/dev-ruby/thor/thor-1.5.0.ebuild
+++ b/dev-ruby/thor/thor-1.5.0.ebuild
@@ -3,7 +3,7 @@
 
 EAPI=8
 
-USE_RUBY="ruby32 ruby33 ruby34"
+USE_RUBY="ruby32 ruby33 ruby34 ruby40"
 
 RUBY_FAKEGEM_RECIPE_TEST="rspec3"
 RUBY_FAKEGEM_DOCDIR="rdoc"