A vehicular vision system includes a video display screen disposed behind a transflective mirror reflector of an electrochromic mirror reflective element of an interior rearview mirror assembly. Image data captured by a rearward-viewing camera is provided to the mirror assembly as digital signals carried by a coaxial cable. Electronic circuitry of the mirror assembly includes (i) auto dimming circuitry and (ii) video processing circuitry. The video display screen (i) displays at a left display region video images derived from captured image data to display a scene occurring in a left side lane, (ii) displays at a right display region video images derived from captured image data to display a scene occurring in a right side lane and (iii) displays at a middle display region video images derived from captured image data to display a scene occurring rearward of the vehicle in the lane the equipped vehicle is travelling in.