diff --git a/lib/irb/color.rb b/lib/irb/color.rb
index ccb9002c23..40e84e1f87 100644
--- a/lib/irb/color.rb
+++ b/lib/irb/color.rb
@@ -38,7 +38,7 @@ module IRB # :nodoc:
 
     class << self
       def colorable?
-        $stdout.tty? && ENV.key?('TERM')
+        $stdout.tty? && ENV.key?('TERM') && ENV['TERM'] != 'dumb'
       end
 
       def inspect_colorable?(obj)