A method for measuring application responsiveness measures the time elapsed between receiving and processing a trailing tag message inserted into the application's message queue. The method receives a message, generates a trailing tag message associated with the message, and inserts the trailing tag message into the application's message queue. The trailing tag message includes a timestamp indicating when the trailing tag message was queued. A default message handler calculates the time elapsed between when the trailing tag message was queued and when the trailing tag message was processed. The elapsed time may then be used to calculated system responsiveness.