diff --git a/openapi_parser.gemspec b/openapi_parser.gemspec
index 4049d7e..1c931aa 100644
--- a/openapi_parser.gemspec
+++ b/openapi_parser.gemspec
@@ -37,6 +37,4 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "steep"
   # for steep + ruby-head
   spec.add_development_dependency 'base64', '~> 0.2.0'
-  # https://github.com/soutaro/steep/issues/466
-  spec.add_development_dependency "activesupport", '~> 6.0'
 end