Kris Jenner -- My Kids All Have Big Heads

Kris Jenner celebrated her birthday in Las Vegas with Kim Kardashian, Kendall Jenner, Kylie, Kourtney, Khloe and Rob -- well, sort of.

Mama Jenner partied her face off at 1 OAK in Sin City for her 59th b-day with new man-squeeze Corey Gamble ... as well as Scott Disick, Alec Monopoloy and Jonathan Cheban -- but her famous kids were nowhere in sight.

So Kris took a pic with their giant heads.

Still beats that embarrassing onesie.