An exterior rearview mirror assembly configured for mounting at a vehicle includes a mounting arm, an electrically operated actuator at one end of the mounting arm, an attachment portion at the other end of the mounting arm, and an exterior mirror head movable relative to the mounting arm via the actuator. The exterior mirror head includes an exterior mirror reflective element attached at an attachment plate of the exterior mirror head. The exterior mirror reflective element attached at the attachment plate moves in tandem with movement of the exterior mirror head relative to the mounting arm when the driver of the equipped vehicle operates the actuator. The attachment plate of the exterior mirror head includes wall structure that extends from the front side of the attachment plate. No part of the exterior mirror head encroaches onto or overlaps the outermost side of the exterior mirror reflective element.