Disclosed is a rear view mirror assembly of the antiglare, "day or night", type which is readily attachable, such as to the face of an existing rear view mirror in a motor vehicle.The mirror assembly comprises a mirror unit (26) operable between two angularly displaced reflective positions. A cam lever (24) comprising first and second cams (48, 54) cooperates with first and second cam followers (36, 38) to move the mirror unit between the two positions. The mirror assembly preferably includes adhesive strip means (22) to secure the assembly to a support. The cam followers are preferably located on the rear wall (40) of the mirror unit such that vertical movement of the cam lever pivots the mirror unit between the operable positions, one for day driving and one for night driving. This simple, vertical actuating movement minimizes forces tending to displace the mirror assembly from the support.