An airbag assembly for a vehicle that includes a housing, an airbag supported by the housing, a deflector pivotally coupled to the housing, and a lock between the deflector and the housing. The lock is moveable relative to the deflector and the housing from an unlocked position disengaged with at least one of the deflector and the housing to a locked position engaged with both the deflector and the housing. The deflector may allow the airbag to deploy, without deflecting the airbag in response to one type of sensed impact, e.g., a full-width frontal impact, and may deflect the airbag in response to another type of sensed impact, e.g., oblique frontal impact.