A generator belt drive of an internal combustion engine, having a generator arrangement with a generator (1) having a belt pulley (6) and a belt tensioner (2). The generator arrangement includes the following: —a first tensioning lever (8) with a first tensioning roller (4), —a second tensioning lever (9) with a second tensioning roller, these tensioning rollers being arranged in front of and behind the belt pulley in a circulating direction of the belt (3) and applying a pretensioning force onto the belt, —a spring (7) arranged between the tensioning levers and which moves the tensioning rollers towards each other, thereby generating the pretensioning force, —and a locking arrangement (11), by which the tensioning levers can be locked relative to each other in a position in which the tensioning rollers are moved away from each other, thereby reducing or canceling the pretensioning force. The generator arrangement also includes an additional locking element by which one of the tensioning levers can be locked relative to the generator that either—is a starter generator (1) and the generator belt drive has a decoupler that is arranged on the generator or on a crankshaft of the internal combustion engine and decouples a rotating starter generator mass from the crankshaft with the support of the belt tensioner, —or has no starter mode.