Does Ant-Man and the Wasp Have a Post-Credit Scene?

Yes, there are extra scenes during, or after, the end credits of Ant-Man and the Wasp.

There are 2 scenes after the credits.

The 1st comes about 2 minutes after the credits start, and lasts for 2 minutes. (It is essential to the story. You must stay for this one.)

After the credits end, there's a super short extra that you may not need to wait for, however it DOES continue the theme at the end of the Infinity War. So SPOILER ALERT JUST IN CASE:

We see a giant ant playing drums as we pan around Scott's otherwise, silent, empty house for a few seconds. The TV is on the emergency alert channel (and I think we hear alert danger sirens in the background). Fade. Then the title card reads, "Ant Man and the Wasp will return" — and after a beat, it adds a question mark.

The credits run for approximately 10 minutes.