The invention specifies an electrical machine (1, 1a . . . 1c) which comprises a housing (8), a stator (5) which is arranged in the housing (8) and a rotor (3) which is rotatably mounted in the housing (8). At least one first coolant duct (9) of a first cooling circuit (15) and at least one second coolant duct (10, 10a, 10b) of a second cooling circuit (16) are arranged in the region of the stator (5) in the housing (8). In this case, the coolant ducts (9, 10, 10a, 10b) and the housing (8) form a heat exchanger between the first cooling circuit (15) and the second cooling circuit (16). In addition, the invention specifies a gear motor comprising the electrical machine (1, 1a . . . 1c), in which gear motor the transmission is hydraulically connected to the at least one second coolant duct (10, 10a, 10b) of the second cooling circuit (16). The invention also specifies a vehicle (27) which is driven by the said electrical machine (1, 1a . . . 1c) or by the said gear motor.