A wing mirror unit for a motor vehicle comprising a mirror foot and a mirror housing connected to the mirror foot. The mirror housing is adjustable between a folded orientation and an unfolded orientation. The wing mirror unit further includes an actuator arranged to move adjacent surfaces of the mirror housing and the mirror foot transversely with respect to each other between a first position, in which the adjacent surfaces of the mirror housing and the mirror foot form a slit, and a second position, in which the adjacent surfaces abut each other.