The present invention relates to an adapter (1) for a wiper system (6), comprising at least a side wall (10) and an upper wall (12) having at least one common edge between them, the side wall (10) and the upper wall (12) helping to define an inner volume of the adapter (1), the adapter (1) comprising a first inner wall (20) and a second inner wall (66) helping to delimit, at least partially, a receiving area (26) intended to receive the connector (8), the adapter (1) comprising at least one receiving housing (32) which is intended to receive the arm and which has a rectangular cross section defined by two major sides (33) and two minor sides (31), characterized in that a straight line (D) passing through one of the major sides (33) cuts the receiving area (26) intended to receive the connector (8).