diff --git a/lib/irb/completion.rb b/lib/irb/completion.rb
index 97f97dfafe..b3b2ecf924 100644
--- a/lib/irb/completion.rb
+++ b/lib/irb/completion.rb
@@ -215,7 +215,7 @@ module IRB
           select_message(receiver, message, proc_candidates | hash_candidates)
         end
 
-      when /^(:[^:.]*)$/
+      when /^(:[^:.]+)$/
         # Symbol
         if doc_namespace
           nil
diff --git a/test/irb/test_completion.rb b/test/irb/test_completion.rb
index b93b5e804a..c909b143a4 100644
--- a/test/irb/test_completion.rb
+++ b/test/irb/test_completion.rb
@@ -292,6 +292,8 @@ module TestIRB
       _ = :aiueo
       assert_include(IRB::InputCompletor.retrieve_completion_data(":a", bind: binding), ":aiueo")
       assert_empty(IRB::InputCompletor.retrieve_completion_data(":irb_unknown_symbol_abcdefg", bind: binding))
+      # Do not complete empty symbol for performance reason
+      assert_empty(IRB::InputCompletor.retrieve_completion_data(":", bind: binding))
     end
 
     def test_complete_invalid_three_colons