A vehicular trailering assist system includes a vehicle rear backup camera disposed at a rear portion of a vehicle and viewing at least rearward of the vehicle. A trailer hitched to the vehicle includes a trailer rear camera disposed at a rear portion of the trailer and viewing at least rearward of the trailer. The control displays at a display device in the vehicle a surround view image using an avatar of the vehicle and an avatar of the trailer. The control stitches images derived from image data captured by the vehicle rear backup camera and images derived from the trailer rear camera to provide a transparent trailer view, and the display device displays transparent trailer view video images. Responsive to the vehicle being shifted into a reverse gear, the display device automatically displays rear backup images derived from image data captured by the trailer rear camera.