The star star-studded party went down Monday night in L.A. at Nightingale Plaza, with a glow-in-the-dark theme ... glowing jello shots, glow drink cups, dancers, the works.

Check out the video. The Migos rapper had the spotlight as he took the stage, rapped some songs and helped folks sing happy Bday to him.

There were a whole bunch of glowing accessories like bracelets, glasses, rings and sticks to go along with the theme. In true Quavo fashion, some of his amigos were able to sip on some drunks like the 'Huncho Rita' and the 'Cheat Code'.

Among the celebs there were Travis Scott, Offset and Takeoff ... and yep you guessed it, actress Karrueche Tran. As you know, folks have speculated that Karrueche and Quavo are indeed a thing, after they were spotted having a romantic dinner and taking a vacation to St. Martin back in January.

Of course, Karrueche told us the two are just friends and nothing more ... but we aren't buying it just yet! Either way, she was sure to pull up and celebrate the birthday boy.

Quavo's actual birthday is April 2 ... and he celebrated in the ATL with the Atlanta Hawks, but hey, the party continues.