A vehicular interior rearview mirror assembly includes a mirror head adjustably attached at a mounting base. The mirror head includes a mirror reflective element having a reflector-coated glass substrate having a front side and a rear side separated by a thickness of the glass substrate. A driver monitoring camera is accommodated by the mirror head and views through a camera region of the glass substrate of the mirror reflective element. A refraction-compensating element is disposed between a lens of the driver monitoring camera and the camera region of the glass substrate of the mirror reflective element. The refraction-compensating element has a first side and a second side that is not parallel to the first side. The refraction-compensating element offsets refraction of light that passes through the camera region of the glass substrate of the mirror reflective element.