A seat includes: a backrest configured to support a back of a seated occupant; a headrest provided to an upper portion of the backrest and configured to support a back of a head of the seated occupant; an overhang portion configured to overhang forward so as to laterally cover the head of the seated occupant from a side portion of the headrest; an overhang adjustment mechanism capable of adjusting an overhang amount of the overhang portion; and a height adjustment mechanism capable of adjusting a height position of the headrest with respect to the backrest.