The invention relates to a tower or a tower segment of a wind turbine, having a door for entering the inside of the tower, comprising a door frame, which has a door opening that is preferably closed by a door leaf. The Invention further relates to a door frame for a door of a tower of a wind turbine, said frame having a door opening that is preferably closed by a door leaf, and to a wind turbine having a tower, a door provided for entering the inside of the tower, and a staircase leading to the door on the outside of the tower, preferably of a tower described above. The underlying object of the invention is to provide an air passage opening in at least one advantageous location. This object is achieved according to the invention in that the door frame has at least one air passage opening, particularly an air inlet opening.