diff --git a/active_admin_theme.gemspec b/active_admin_theme.gemspec
index 106efe1..a41ff9a 100644
--- a/active_admin_theme.gemspec
+++ b/active_admin_theme.gemspec
@@ -25,5 +25,5 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "activeadmin", ">= 3.0", "< 4.0"
+  spec.add_dependency "activeadmin", ">= 3.0", "< 4.0.0.a"
 end