An assembly for a vehicle includes a vehicle floor and a vehicle roof spaced from the vehicle floor. A pillar extends from the vehicle floor to the vehicle roof. The assembly includes an airbag supported by the pillar. The airbag is inflatable from the pillar from an uninflated position to an inflated position. The assembly includes a seat supported by the vehicle floor adjacent the pillar. The airbag extends around the seat when in the inflated position.