A socket assembly comprises a socket and a pick up cap attached on the socket. The socket has an insulative housing with sidewalls, and the sidewalls have a plurality of protrusions extending upwardly and formed with end surfaces. The pick up cap comprises a plurality of cutouts with inner side surfaces. The inner side surface of the cutout abuts against corresponding end surface of insulative housing to position the pick up cap on the insulative housing. An interference force created between the cutout and the protrusion extends along an extending direction of corresponding sidewall.