A vehicular exterior rearview mirror assembly includes a mirror head and a mounting base, with the mirror head having a mirror casing and a reflective element, and with the mounting base configured for attachment at a vehicle. A camera module is disposed at the mirror head and includes a camera having a field of view and operable to capture image data. The camera module is extendable and retractable relative to the mirror casing. With the camera module retracted, the camera module is oriented such that the field of view of the camera encompasses a blind spot region at least at the body side of the vehicle. With the camera module retracted, an inboard limit of the field of view of the camera partially overlaps an outboard limit of a field of view provided to a driver of the vehicle by the reflective element.