Megan Thee Stallion's a savage ... but, that doesn't mean she won't let loose and party -- and, we've got all her hottest shots for you on her milestone birthday.

The rapper turned 30 Saturday ... and, she's supplied years of some of the steamiest photos around  -- letting it all hang out in tiny cocktail dresses and even smaller bikinis.

Check out this pic of MTS wearing a tiny lingerie dress ... booty popping out of the barely-there fabric.

And, never forget Meg's from Texas ... 'cause she certainly doesn't when she's modeling in a cowboy hat on a pristine white, sandy beach.

Megan's been relatively quiet since releasing her fourth studio album -- "Megan: Act II" -- featuring hit tracks like "Neva Play" and "Bigger in Texas."

While she hasn't announced a world tour yet, we do know she'll be at Coachella in April ... rocking Indio with her impressive beats.