diff --git a/lib/irb/completion.rb b/lib/irb/completion.rb
index 0e34fc63aa..35767feeb7 100644
--- a/lib/irb/completion.rb
+++ b/lib/irb/completion.rb
@@ -373,7 +373,7 @@ module IRB
         if doc_namespace
           "String.#{candidates.find{ |i| i == message }}"
         else
-          select_message(receiver, message, candidates)
+          select_message(receiver, message, candidates.sort)
         end
 
       else
@@ -390,7 +390,7 @@ module IRB
         else
           candidates = (bind.eval_methods | bind.eval_private_methods | bind.local_variables | bind.eval_instance_variables | bind.eval_class_constants).collect{|m| m.to_s}
           candidates |= ReservedWords
-          candidates.grep(/^#{Regexp.quote(input)}/)
+          candidates.grep(/^#{Regexp.quote(input)}/).sort
         end
       end
     end
diff --git a/test/irb/test_completion.rb b/test/irb/test_completion.rb
index fb10870820..8d7476b8f5 100644
--- a/test/irb/test_completion.rb
+++ b/test/irb/test_completion.rb
@@ -208,5 +208,16 @@ module TestIRB
       assert_include(IRB::InputCompletor.retrieve_completion_data("String.new", bind: binding), "String.new")
       assert_equal(IRB::InputCompletor.retrieve_completion_data("String.new", bind: binding, doc_namespace: true), "String.new")
     end
+
+    def test_complete_sort_variables
+      xzy, xzy_1, xzy2 = '', '', ''
+
+      xzy.clear
+      xzy_1.clear
+      xzy2.clear
+
+      candidates = IRB::InputCompletor.retrieve_completion_data("xz", bind: binding, doc_namespace: false)
+      assert_equal(candidates, %w[xzy xzy2 xzy_1])
+    end
   end
 end