A diagnosis of masked bilateral superior oblique palsy (MBSOP) is established when signs of SOP appear in the normal eye of a patient after strabismus surgery for SOP in the contralateral eye. Despite the absence of signs of bilaterality before surgery, a palsy will develop in the previously unaffected eye in 10% or more of the patients undergoing surgery. This paper examines the clinical profiles and results of surgical management of 14 patients with MBSOP.