A vehicular interior rearview mirror assembly includes a mirror head having a mirror reflective element with a transflective mirror reflector. A video display device is disposed rearward of the mirror reflective element and has a display screen that occupies at least 85 percent of a reflective region of the transflective mirror reflector that is visible to a driver of the vehicle when viewing the mirror reflective element. The video display device is operable to display video images captured by a rearward viewing camera of the vehicle. When the video display device is operated to display video images, light emitted by the video display device passes through the transflective mirror reflector of the mirror reflective element for viewing of displayed video images by the driver of the vehicle viewing the mirror reflective element. Light emitted by the video display device may exit the mirror reflective element as circularly polarized light.