Abstract: A portable pet barrier for temporary installation in an automotive vehicle, the vehicle having seating arrangements which feature removable headrests. The barrier is intended to restrict the movement of medium to large sized pets, for example, dogs, to portions of the vehicle not occupied by the driver or passengers. Typically, the barrier is installed across the backrest of the rear seating of a sport utility vehicle (SUV), minivan, or station wagon to confine the pet to the rear luggage/cargo portion of the vehicle. Without using tools or making threaded adjustments, installation of the barrier entails the engagement of two or more slidable bolts with coaxially aligned headrest sockets, the sockets becoming available for use after removal of the headrests. Inserted into headrest sockets and frictionally in contact with the resilient, compliant obstructive panel of the barrier, the bolts fasten and maintain position of the barrier across the top of the vehicle backrest.