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.

So, happy birthday, Megan ... hopefully the cake or pie tastes the sweetest today!