An electrical connector includes an insulative housing defining a space. A connection module is received within the space. The connection module includes a pair of contact modules commonly sandwiching a grounding module therebetween in the transverse direction. Each contact module includes a plurality of contacts integrally formed within the corresponding insulative wafer via insert-molding. The grounding module includes a grounding plate embedded within an insulative wafer. The grounding plate forms a plurality of fingers respectively electrically and mechanically connecting to the corresponding grounding contacts of the contact modules. The wafer forms a plurality of transverse grooves to receive corresponding grounding bars each having a plurality of inward parts respectively mechanically and electrically connecting to the grounding plate, and a plurality of outward parts respectively mechanically and electrically connecting to the grounding contacts of the contact modules.