A vehicular interior rearview mirror assembly includes a mirror head adjustably attached at a mounting base. The mirror head includes a prismatic mirror reflective element having a wedge-shaped, reflector-coated glass substrate having a front side and a rear side separated by a thickness of the glass substrate, with the thickness of the glass substrate varying between a lower edge region of the glass substrate and an upper edge region of the glass substrate. A driver monitoring camera is accommodated by the mirror head and views through the prismatic mirror reflective element. A refraction-compensating element is disposed between a lens of the driver monitoring camera and the rear side of the glass substrate of the prismatic mirror reflective element. The refraction-compensating element is a wedge-shaped element that offsets refraction of light that passes through the wedge-shaped, reflector coated glass substrate of the prismatic mirror reflective element.