A vehicular exterior rearview mirror assembly includes a mirror head adjustably mounted at a mounting arm via a link that pivotally attaches at one end to the mirror head and pivotally attaches at another end to the mounting arm. With the mounting arm attached at the side of a vehicle, the mirror head is adjustable relative to the mounting arm between a retracted position and an extended position. An adjustment mechanism is operable to adjust the mirror head relative to the mounting arm and includes an electrically operated motor that operates to pivotally adjust the link, which swings the mirror head along an arcuate path. When the motor is operated to pivotally adjust the link to adjust the mirror head relative to the mounting arm, an angle of the mirror head relative to the side of the vehicle at which the vehicular exterior rearview mirror assembly is attached is also adjusted.