A patient developed severe lower eyelid ectropion after a bilateral levator aponeurosis and Müller's muscle advancement-and-truck blepharoptosis procedure and bilateral attachment of the lateral canthi to the lateral canthal tendons. The cause of this ectropion was detachment of Müller's muscle and capsulopalpebral fascia from the inferior tarsus and recession of these tissues into the orbit. This left the inferior tarsal border with only redundant conjunctiva attached to it, which could not maintain it in a downward direction; thus, an ectropion occurred. Müller's muscle and capsulopalpebral fascia were detached from the inferior tarsus and recessed 15 mm into the orbit. Reattaching Müller's muscle and capsulopalpebral fascia to the inferior tarsus relieved the ectropion.