A removable seat for a truck bed. The seat has front and back lateral runners, the front runner being the higher. The runners are telescopic in construction. Four attachments, two for each runner, are attached to the truck bed, and the runners are held to the truck bed by them. A flexible seat member has a slack length and extends between the runners. It forms a cavity to receive an occupant. A pair of flexible inelastic side panels are attached to the seat member, and a pair of side bands of flexible inelastic material having a shorter length than the slack length are supported by and extend between the runners. Together, the panels with bands make a side restraint and arm rest. A cushion is pivotally attached to the sheet adjacent to the higher runner, so it can be pivoted to protect an occupant from striking that runner. The attachments are preferably sockets to receive laterally extending tongues that are carried by the runners. Deflection of the runners enables the tongues to be retained more reliably in the sockets.