Kylie Jenner is Dropping a Fortune on Baby Clothes

Kylie Jenner's on a mission to outfit her daughter in the swaggiest baby gear money can buy -- as in $70,000 -- and she's done most of it behind closed doors.

Sources close to Jenner tell TMZ the mom-to-be has made online baby shopping a habit ... surfing the web for high-end designer clothing and baby accessories. We're told she's already got one huge closet filled and plenty more is on the way.

Kylie's also venturing out to OG brick and mortar retailers ... she hit up a few stores in the San Fernando Valley.

We're told in all, Kylie's dropped north of $70k. One Kylie source familiar with the purchases tells TMZ, "This is gonna be the best dressed kid you've ever seen."