Does The Gentlemen Have a Post-Credit Scene?

Yes, there are extra scenes during, or after, the end credits of The Gentlemen.

The credits scroll for about one minute. After that, the full uncensored music video for the in-film song "Box in the Bush," by The Toddlers, plays on one side of the screen, with the credits on the other side.

There is nothing after the video ends.

The credits run for approximately 5 minutes.