Fifth wheel

In a fifth wheel coupling (1) for coupling a tractor unit (2) to a semi-trailer (3), with a fifth wheel plate (4) for mounting on the tractor unit (2) and an engagement element (5) for mounting on the semi-trailer (3), it is proposed that an angle measuring device (6) comprising a rotation angle sensor (7) for measuring the rotation angle between the engagement element (5) and the fifth wheel plate (4) is provided.