A ventilation device has a frame (12) made of a first material component, and a non-return flap element (14) made of a second material component, wherein the first material component is harder than the second material component. The non-return flap element (14) includes a movable non-return flap (18), which is arranged such that it exclusively rests against the non-return flap element (14) or the ventilation device (10) is mountable on a vehicle component (28), wherein that part of the ventilation device (10) which engages the vehicle component (28) is part of the non-return flap element (14).