A socket connector includes a socket body, a plurality of contacts received in the socket body; and a pick-up cap mounted upon the socket body. The socket body includes a base and a first sidewall and a second sidewall respectively located by opposite sides of the base. The first sidewall and the second sidewall are respectively formed with a first protrusion and a second protrusion. The pick-up cap includes a cover section and a first flange and a second flange which respectively extend downwardly from opposite sides of the cover section and which are respectively engaged with the first sidewall and the second sidewall of the socket body. The first flange and the second flange are respectively formed with a first notch and a second notch arranged in asymmetrical manner and engaged with the first protrusion and the second protrusion, respectively.