A seat supporting assembly for use in vehicles such as tractors or the like wherein the seat is surrounded in relatively close relationship by obstructions such as controls which make it difficult for the vehicle operator to get into and out of the seat. The seat supporting assembly provides means for supporting the vehicle seat such that the seat may be moved rearwardly and then rotated to permit access to or egress from the seat. The assembly also provides means which prevent rotation of the seat unless it has been moved to its furthest rearward position. The seat supporting assembly further includes means to facilitate vertical adjustment of the seat and to secure the seat in its desired vertical position.