Don't worry Thor fans, you'll get a little extra time with your Asgardian prince once the credits roll on Thor: Ragnarok (opens in new tab). Which is really just my fancy way of saying yes, Thor 3 has a post-credits scene. According to Forbes' Scott Mendelson, the upcoming MCU film actually has two: one that ties into the plot, and one that's a straight-up joke.
The first is slightly plot-related but the second is a straight joke.October 10, 2017
It sounds like Ragnarok is following Spider-Man: Homecoming (opens in new tab)'s example by having the plot-related scene appear partway through the credits while the joke is a send-off saved for the very end. Mendelson couldn't say what the scenes depicted, but he did say what they weren't (opens in new tab): a teaser for Avengers: Infinity War (opens in new tab).
Based on the Infinity War teaser shown at San Diego Comic-Con, we know the god of thunder does bump into the Guardians of the Galaxy at some point in the future, but it doesn't sound like that will be teased in Ragnarok. Black Panther (opens in new tab) is actually the next scheduled MCU film (set to premiere February 2018) but seeing how Thor has never met T'Challa, I'd be surprised if either scene related to that film.
All that being said, it's not unheard of for a movie company to save some of the fun for wider audiences. It's possible there will be more than what Mendelson has reported here when Thor: Ragnarok debuts in a cinema near you.
Ever since Robert Downey Jr. tore up the screen as Tony Stark in 2008's Iron Man, Marvel has used the time that used to be reserved solely for a movie's credits to tease future films, give fans a little closure, or just make a funny joke.
The trend has become so pervasive that there are now entire websites (opens in new tab) dedicated solely to answering the question, 'Does <insert movie here> have a post-credits scene?' And now here we are, speculating on not one, but two post-credits stingers. The times they are a-changin'.