An assembly for a vehicle includes a vehicle body having a body side. A seat is adjacent the body side. The seat includes a seatback and a seat bottom extending in a seat-forward direction from the seatback. The seatback and seat bottom defines an occupant-seating area. A head airbag is mounted to the seatback and is inflatable over the occupant-seating area. A knee airbag is mounted to the body side. The knee airbag is inflatable from the body side to an inflated position. The knee airbag in the inflated position is adjacent to the seat bottom in the seat-forward direction from the seat bottom.