Trabeculotomy has received increasing interest as a glaucoma procedure not only in congenital glaucoma but also in adult-onset open-angle glaucoma. In this review, the development, surgical technique, mechanism of action, and results after trabeculotomy in different types of glaucoma are described. Combined trabeculotomy and trabeculectomy and combined cataract and trabeculotomy techniques are discussed. Some remarks are given on laser trabeculotomy ab interno and other developments of trabecular surgery.