Presented herein is a sheet turning unit (1) comprising a first sheet conveyor device (2a) for transporting a sheet at least along a first transport path (B1) in a first plane (E1), and comprising a second sheet conveyor device (2b) for transporting the sheet along a second transport path (B2), said second transport path extending at an angle of 90° with respect to the first transport path (B1) and, in sum, describing a curve of 180°, whereby the starting point of said curve is located in the first plane (E1) and the end point of said curve is located in a second plane (E2) that is different from the first plane, and comprising a third sheet conveyor device (2c) for transporting the sheet along at least a third transport path (B3). As a result of this, the leading edge of the sheet remains in front even after the turning operation, and a precisely functioning and reliable sheet turning unit is being provided. Furthermore, advantageous embodiments of the first and third sheet conveyor devices are described, said devices enabling the transport of a sheet in two directions. The advantageous embodiments of the first and third sheet conveyor devices are compact and simple in design and can be controlled easily. The advantageous embodiments of the first and third sheet conveyor devices comprise a sheet transport body that, by means of a rotating mechanism arranged in the sheet transport body, can be rotated about a first rotational axis and a second rotational axis, said axes extending through one point of intersection and being perpendicular to one another.