Minnesota Governor Tim Walz appeared to call Elon Musk a "gay guy" on the campaign trail ... but the billionaire is brushing off the apparent gaffe.

Kamala Harris' running mate was giving a speech Friday in Detroit, Michigan when he started talking about Elon getting a big tax cut.

Walz appears to say ... "If you're a billionaire, Elon Musk for example, say. That guy, that gay guy got" before stopping himself and laughing ... playing it off by saying, "Michigan knows that word."

The crowd laughs too and then Walz changes the reference to Elon, saying ... "That dude got a tax cut."

Walz's apparent flub is going viral on social media and lots of folks are convinced he meant to call Elon a "gay guy."

Elon's seen the clip, though he doesn't have a big issue with it ... posting on X, "I have no problem being called gay tbh."