A problem that only wealthy (typically white) kids have. These problems tend to be trivial and annoying, as opposed to real problems, which can be life threatening (i.e. "I have no food."). Can be abbreviated to WKP, for easy use.
White kid: I have no place to smoke my weed.
Other kid: White kid problem.
White kid: My dad's mega-yacht isn't big enough!
Other kid: WKP