Disclosed is a conveyor roller (1) which comprises a shaft (2), a roller body (3) which is mounted such that it can be rotated about the shaft (2), and a protective cap (4). The protective cap (4) has a disk-shaped first section (5) for covering the interior of the roller body (3), which is arranged fixedly with respect to the shaft (2) and is oriented normally with respect thereto, and a channel-like or roof-like second section (6) which is arranged obliquely with respect to the shaft (2) and runs over a part length of the roller body (3) such that it is spaced apart radially from the latter. Furthermore, a conveyor system (12) with a conveyor roller (1) is disclosed, in which conveyor system a connecting cable (7) of the conveyor roller (1) is run in a curve or a loop to an electrical interface (8, 17) with a connector box (15) of the conveyor system (12), wherein the lowest point of the curve/the loop is located below said interface (8, 17).