An electrical connector defines perpendicular first direction and second direction and includes a housing and a plurality of contacts. The housing includes a base portion and a first mating portion. The mating portion defines opposite first mating face and second mating face. The contacts are arranged in the housing in the second direction and include mating portions respectively exposed upon the first mating face and the second mating face and tails protruding from the housing. The contacts include several high-speed signal groups and each includes a pair of signal contacts and a grounding contact. The mating portions of the pair of signal contacts are located at the second mating face while the mating portion of the grounding contact is located at the first mating face. Three mating portions of each high-speed signal group are shaped as a triangle from a view along the first direction.