Abstract: Mobile signs/billboards designed to attach to the back end of a vehicle are disclosed comprising a mounting device that is mounted to the back end of a vehicle via the holes for fixing a license plate, and a sign or billboard supported by the mounting device. The signs are designed in a variety of shapes and sizes to provide a display for advertisement or personal messaging. The sign/billboard can be inserted or removed quickly from the mounting device. While the sign/billboard is supported by the mounting device at the back end of the vehicle, the license tag is affixed elsewhere on the mounting device for full viewing and lighting. The mounting device remains on the vehicle until easily removed whereupon the license plate can be reattached to the vehicle. The mounting device comprises an inner pocket for easy insertion and removal of signs and billboards. Lighting may be wired with the vehicle or use solar power or batteries to providing lighting for the sign/billboard.