The momager kicked off the gushing birthday tributes to the model in a sentimental IG post ... heaping endless praise on her "beautiful, kind, generous, giving, smart, talented, creative, amazing, thoughtful" daughter.

Of course, a collection of Kendall's adorable childhood snaps accompanied the extravagant compliments -- par for the course for the KarJenners, really.

Kris says she's blessed to be her mother -- and we're sure Kendall following in her sisters' mega-business brand footsteps with her 818 Tequila venture has something to do with it.

Not that she needed it ... with a $45M net worth, she's a regular topper on Forbes' annual list of highest-paid models after working with virtually every fashion brand out there.

Meanwhile, Kendall's sisters have been slow on the ground with their birthday tributes to KJ -- but they're all busy running empires, so we'll let them off the hook.

But the supermodel's BFF Hailey Bieber spent all night rolling out the dough to make pumpkin-flavored iced buns for her ... which already appeared to be half eaten when presented to her. What a "sicko" -- Kendall's words, not ours.