An electrical connector includes an insulating seat and at least one conductive terminal provided therein. The insulating seat includes a rear wall and two side walls, surroundingly forming a mating space. Each side wall includes an extending arm and an elastic arm. The elastic arm has a first arm extending forward from the extending arm and a second arm bending reversely from the first arm and extending backward. The second arm is connected to the rear wall. An opening slot is formed between the first arm and the extending arm and runs forward therethrough. A through slot is formed between the second arm and the first arm. A buckling portion is formed at a side of the second arm away from the first arm to correspond to the through slot and the opening slot in a left-right direction. The conductive terminal has a contact portion exposed to the mating space.