The invention relates to a ventilation duct (20) for a ventilation system (18) of a vehicle, in particular a rail vehicle (10) for passenger transport, with a duct wall (26) delimiting the duct (20) outwardly and a flexible sheet material (36) arranged in the interior of the duct (20), which—as seen in cross-section of the duct (20)—extends from a first fastening point (38) on the inner circumference of the duct wall (26) to a second fastening point (40) on the inner circumference of the duct wall (26) arranged at a distance from this first fastening point (38) and divides the duct (20) into a first partial duct (42) for cold air and a second partial duct (44) for warm air, whereby the cross-section of each of the partial ducts (42, 44) can be enlarged under reduction of the cross-section of the respective other partial duct (44, 42) by means of a deformation of the flexible sheet material (36) controllable solely by the air pressure and volume flow conditions in the partial ducts (42, 44). It is provided that the two fastening points (38, 40) are arranged on the same side (30) of the duct wall (26), whereby the flexible sheet material (36) and this side (30) of the duct wall (36) form the first partial duct (42) for the cold air. The invention further relates to a vehicle, in particular a rail vehicle (10) for passenger transport, with a ventilation system (18) that has a ventilation duct (20) arranged above an interior space (16) of the vehicle (10).
