A vehicle seat includes, at each side portion of a seatback frame, a side frame base portion that forms a side portion of the seatback frame, and that extends in a seat up-and-down direction; an outer side flange portion that is formed at a seat forward side of the side frame base portion, and that is inflected to a seat width direction outer side from the side frame base portion; and an inner side flange portion that is formed at a seat rear side of the side frame base portion, and that is inflected to a seat width direction inner side from the side frame base portion, a corner portion of the inner side flange portion curving in a circular arc shape.