The present disclosure is directed to a staircase assembly for a vehicle, such as a recreational vehicle (RV). The stair case assembly includes a pair of substantially flat, spaced apart, support brackets that are configured to mount to a vehicle, and define a storage space for a linkage system and associated plurality of steps. The linkage system is configured to move the plurality of attached steps from a vertically orientated stored position to a horizontally oriented deployed position extending outwardly from the vehicle allowing a person to easily enter and exit the vehicle.