An electrical connector that includes a housing configured to be coupled to a mating connector. The connector has signal contacts held in signal contact openings. The signal contacts are arranged in arrays of quad groups. Each of the quad group has a set of four contacts arranged in row pairs and column pairs. The signal contacts of each quad group are configured to carry relational signals with each other signal contact in the quad group. Each signal contact is configured to electrically couple to a signal contact of the mating connector. The connector also includes ground shields held in corresponding ground shield openings. The ground shields have walls surrounding a corresponding quad group of signal contacts and provides electrical shielding from adjacent quad groups of signal contacts. The ground shields have mating ends for mating with corresponding ground contacts of the mating connector.