An electrical connector assembly 10 includes a receptacle member 12 and a pin header 60. The receptacle member 12 has housing means 14 including an inner body portion 22 and two opposed outer side walls 24, which together define elongate cavities 36 between inner body section 22 and respective outer side walls 24; and a plurality of first contact terminal members 40 disposed in inner body portion 22 and a plurality of second contact terminal members 46 disposed in the elngate cavities 36. The pin header 60 includes a housing member 62 having a plurality of third electrical contact terminal members 78 disposed therein and adapted to mate with the first terminal members and at least one ground bus member 92 disposed continuously along at least one side of pin header housing 62, the bus member 92 being adapted to be received in one of the respective elongate cavities 36 of receptacle member 12 and electrically engage the second terminal members 46 therein, when the receptacle member 12 and pin header 60 are mated.