Abstract: A ventilation device (10), in particular for a vehicle interior, has a frame (12) which includes at least one opening (16), and at least one non-return flap (20), the non-return flap (20) having at least one recess (26) provided thereon through which a holding member (22) provided on the frame (12) extends, and the non-return flap (20), depending on the active pressure differential, being movably adjustable on the holding member (22) between a closed position, in which the non-return flap (20) rests against the frame (12) and closes the at least one opening (16) of the frame (12), and an open position. The holding member (22) is deformable between a mounting position, in which the non-return flap (20) can be mounted to the holding member (22), and a locked position, in which the non-return flap (20) can not be dismounted.