An exterior rearview mirror assembly for a vehicle includes a mirror head and a mounting base, with a camera module disposed at the mirror head. The camera module includes a camera having a field of view exterior of the vehicle when the mirror assembly is attached at the vehicle. The camera module is extendable and retractable relative to a mirror casing of the mirror head. With the camera module retracted and with the mirror assembly attached at the vehicle, the camera module is oriented such that its field of view encompasses a blind spot region at least at the body side of the vehicle. With the camera module extended and with the mirror assembly attached at the vehicle, the camera module may be oriented such that its field of view encompasses a region at least along a body side of a trailer being towed by the vehicle.