diff --git a/resources/scripts/Global.lua b/resources/scripts/Global.lua
index bf88e81..8053150 100644
--- a/resources/scripts/Global.lua
+++ b/resources/scripts/Global.lua
@@ -13,6 +13,10 @@ function onCommandRequiredRankMissingError(additional_information, player)
     player:send_message(string.format("%s\nAdditional information: %s", error_msg, additional_information))
 end
 
+function onUnknownCommandError(command_name, player)
+    player:send_message(string.format("Unknown command %s", command_name))
+end
+
 function split(input, separator)
     if separator == nil then
         separator = '%s'
diff --git a/src/bin/kawari-world.rs b/src/bin/kawari-world.rs
index f5c1aa3..e17bb75 100644
--- a/src/bin/kawari-world.rs
+++ b/src/bin/kawari-world.rs
@@ -564,6 +564,18 @@ async fn client_loop(
                                                                 }
                                                             })
                                                             .unwrap();
+                                                        } else {
+                                                            tracing::info!("Unknown command {command_name}");
+
+                                                            lua.scope(|scope| {
+                                                                let connection_data = scope
+                                                                    .create_userdata_ref_mut(&mut lua_player)
+                                                                    .unwrap();
+                                                                let func: Function =
+                                                                    lua.globals().get("onUnknownCommandError").unwrap();
+                                                                func.call::<()>((command_name, connection_data)).unwrap();
+                                                                Ok(())
+                                                            }).unwrap();
                                                         }
                                                 }