An electrical connector includes an insulative housing and a plurality of contacts. Each contact has a retaining section, a mating section and a crimping section, the insulative housing defines a positioning groove communicated with contact-receiving passageways, the retaining section is provided with an elastic retaining arm extending backwards, a pair of cutouts on both sides of the retaining arm along a transverse direction, and a pair of limiting walls exposed in the cutouts and the positioning groove. When the contacts assembled to the relative contact-receiving passageways, each retaining arm is abutting against a rear inner surface of the positioning groove via a free end thereof to prevent the contact moving backwards, the electrical connector further comprises a retainer, and the retainer defines a plurality of limiting blocks extruding into the positioning groove and the corresponding cutouts, and the limiting blocks are abutting against the relative limiting walls.