A vehicular interior rearview mirror assembly includes a mounting portion, a mirror casing and a mirror reflective element. The reflective element includes a glass substrate having a planar front surface, a planar rear surface and a circumferential perimeter edge around a periphery of the glass substrate that extends across a thickness dimension separating the planar front surface from the planar rear surface. A front perimeter edge portion of the circumferential perimeter edge includes a rounded glass surface circumferentially around the periphery of the glass substrate, with the rounded glass surface at least partially spanning the thickness dimension of the glass substrate. The rounded glass surface has a radius of curvature of at least 2.5 mm. The planar rear surface of the glass substrate is coated with a coating. No portion of the mirror casing overlaps onto the rounded glass surface of the glass substrate.