A 67-year-old white man with a history of right orbital trauma and restrictive strabismus underwent right superior oblique tenectomy for superior oblique restriction. Bleeding was noted from the superior rectus intraoperatively, despite the fact that the muscle was neither exposed nor hooked for the procedure. Subsequent exploration of the muscle revealed a full-width tear across the superior rectus muscle approximately 5 mm posterior to its insertion. The remaining residual distal muscle was removed from the insertion and the proximal end of the torn superior rectus muscle was identified and reattached to the insertion. We postulate that shearing forces exerted by a taut superior oblique tendon were sufficient to tear the overlying superior rectus muscle.