diff --git a/lib/irb/completion.rb b/lib/irb/completion.rb
index af3b69eb2..e69eae1de 100644
--- a/lib/irb/completion.rb
+++ b/lib/irb/completion.rb
@@ -86,6 +86,11 @@ def retrieve_files_to_require_from_load_path
         )
     end
 
+    def command_completions(preposing, target)
+      return [] unless preposing && preposing.match?(/\A\s*\z/)
+      IRB::ExtendCommandBundle.command_names.select { _1.start_with?(target) }
+    end
+
     def retrieve_files_to_require_relative_from_current_dir
       @files_from_current_dir ||= Dir.glob("**/*.{rb,#{RbConfig::CONFIG['DLEXT']}}", base: '.').map { |path|
         path.sub(/\.(rb|#{RbConfig::CONFIG['DLEXT']})\z/, '')
@@ -103,9 +108,10 @@ def inspect
     end
 
     def completion_candidates(preposing, target, _postposing, bind:)
+      commands = command_completions(preposing, target)
       result = ReplTypeCompletor.analyze(preposing + target, binding: bind, filename: @context.irb_path)
-      return [] unless result
-      result.completion_candidates.map { target + _1 }
+      return commands unless result
+      commands | result.completion_candidates.map { target + _1 }
     end
 
     def doc_namespace(preposing, matched, _postposing, bind:)
@@ -177,11 +183,12 @@ def complete_require_path(target, preposing, postposing)
     end
 
     def completion_candidates(preposing, target, postposing, bind:)
+      commands = command_completions(preposing, target)
       if preposing && postposing
         result = complete_require_path(target, preposing, postposing)
         return result if result
       end
-      retrieve_completion_data(target, bind: bind, doc_namespace: false).compact.map{ |i| i.encode(Encoding.default_external) }
+      commands | retrieve_completion_data(target, bind: bind, doc_namespace: false).compact.map{ |i| i.encode(Encoding.default_external) }
     end
 
     def doc_namespace(_preposing, matched, _postposing, bind:)
diff --git a/test/irb/test_completion.rb b/test/irb/test_completion.rb
index 0625c9697..831b030bf 100644
--- a/test/irb/test_completion.rb
+++ b/test/irb/test_completion.rb
@@ -14,6 +14,13 @@ def doc_namespace(target, bind)
       IRB::RegexpCompletor.new.doc_namespace('', target, '', bind: bind)
     end
 
+    class CommandCompletionTest < CompletionTest
+      def test_command_completion
+        assert_include(IRB::RegexpCompletor.new.completion_candidates('  ', 'show_s', '', bind: binding), 'show_source')
+        assert_not_include(IRB::RegexpCompletor.new.completion_candidates(';', 'show_s', '', bind: binding), 'show_source')
+      end
+    end
+
     class MethodCompletionTest < CompletionTest
       def test_complete_string
         assert_include(completion_candidates("'foo'.up", binding), "'foo'.upcase")
diff --git a/test/irb/test_type_completor.rb b/test/irb/test_type_completor.rb
index cf4fc12c9..1ab231fab 100644
--- a/test/irb/test_type_completor.rb
+++ b/test/irb/test_type_completor.rb
@@ -9,6 +9,8 @@
   return
 end
 
+require 'irb/context'
+require 'irb/extend-command'
 require 'irb/completion'
 require 'tempfile'
 require_relative './helper'
@@ -54,6 +56,11 @@ def test_empty_completion
       assert_equal [], candidates
       assert_doc_namespace('(', ')', nil)
     end
+
+    def test_command_completion
+      assert_include(@completor.completion_candidates('  ', 'show_s', '', bind: binding), 'show_source')
+      assert_not_include(@completor.completion_candidates(';', 'show_s', '', bind: binding), 'show_source')
+    end
   end
 
   class TypeCompletorIntegrationTest < IntegrationTestCase