An oil supply system for an aircraft engine, includes at least one oil circuit including an oil tank having a closing valve associated with an outlet opening of the oil tank into a suction line, an oil pump, and at least one consumer to be supplied oil via a pressure line. A negative pressure relief line having a shut-off valve is connected to the suction line for ensuring pressure relief in the suction line after shutdown. Via a diaphragm volume flow limiter alternatively incorporated into the relief line, the suction line can also be connected permanently to the pressure line. A negative pressure occurring in the suction line after shutdown of the engine when the closing valve is closed and the plastic deformation of the suction line as well as a reduction of the pump suction capacity are thus avoided.