An electrical connector includes an insulative housing, a number of signal contacts retained in the insulative housing, a spacer positioned under the insulative housing, and a retainer fastening the insulative housing and the spacer together. The insulative housing has an upper face and a lower face opposite to the upper face. The spacer has a joint face engaging with the lower face and a mounting face opposite to the joint face. The retainer has a top wall affixing to the upper face and a locking barb engaging with the mounting face.