A receptacle connector includes an insulating body, a plurality of terminals and a housing. The insulating body defines a plurality of cavities for receiving the terminals. The housing defines a receiving space for receiving the insulating body and a locking space for fixing a plug connector. Two opposite sides of a top wall of the housing respectively extend sideward to form a pair of wings. The wing defines a locking aperture passing through a top and a bottom thereof. The middle of the top wall protrudes upward to form a locking lump. The middle of the rear of the top wall protrudes upward to form a connecting section adjacent to the rear of the locking lump. The locking aperture, the locking lump and the connecting section respectively buckle with corresponding structures of a fixing device.