DeSean Jackson -- Throwin' Gang Signs with Rapper Nipsey Hussle

Philadelphia Eagles wide receiver DeSean Jackson is a Crip ... and he ain't afraid to show it -- flashing gang signs with rapper (and fellow Crip) Nipsey Hussle.

Jackson and Nipsey were hanging out after a show in Philadelphia this weekend ... when they posed for a photo -- and DeSean threw a hand signal for Rollin' 40s Crips.

FYI -- Nipsey is a member of the Rollin' 60s Crips.

It ain't the first time Jackson has thrown the sign in public -- in fact, this past football season, he threw up the sign during a game against the Washington Redskins.

1:44 PM PT -- Our bad ... initially, we reported DeSean was at the YG party in L.A. In fact, the YG party was the following night in L.A.

Nipsey was at the YG party. DeSean was not.