Cleveland Cavs player Larry Nance Jr. got married at an Ohio courthouse Tuesday and the dress code was as casual as it gets -- Yeezy shoes and Lululemon pants!

There's a story here ... the 25-year-old NBA player and his fiancee, Hailey Pince, were celebrating their 4-year anniversary and decided ... why not get married?

So, they hit the courthouse and made it happen!

"No makeup, hair in a quick ugly pony, Larry in some lulu lemon pants and yeezy’s," Hailey said in an IG post.

But this ain't about saving a buck or two ... Hailey says there's a big destination celebration coming down the pike.

"We needed to get the legal marriage done before our destination wedding and today just seemed like the best day to do it! Happy Four Years! Can't wait for our real wedding!"