The authors document their experience in the management of four cases of Crouzon syndrome and review the anatomical extraocular muscle anomalies noted during surgery. Horizontal strabismus surgery varied in each of the four cases according to individual extraocular muscle abnormalities and usually required two or more procedures. Most cases required significant amounts of treatment, especially when abnormal development of extraocular muscles existed. Compared to normal muscles, the muscles in Crouzon syndrome have pathological changes consistent with collagen degeneration. The authors found the tendon capsule to be thicker than normal and, in some cases, the lateral rectus had fused to the sclera. They found inferior rectus muscle abnormalities to a greater extent than superior oblique. Treatment of amblyopia was important and they reported that, the better the visual acuity, the better the outcome.