diff --git a/mailcatcher.gemspec b/mailcatcher.gemspec
index f733549..577ece3 100644
--- a/mailcatcher.gemspec
+++ b/mailcatcher.gemspec
@@ -35,7 +35,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency "activesupport", ">= 3.0.0", "< 4.1"
   s.add_dependency "eventmachine", "~> 1.0.0"
-  s.add_dependency "haml", ">= 3.1", "< 5"
+  s.add_dependency "haml", ">= 3.1", "< 4.1"
   s.add_dependency "mail", "~> 2.3"
   s.add_dependency "sinatra", "~> 1.2"
   s.add_dependency "sqlite3", "~> 1.3"