The use of lasers is slowly pervading all subspecialties of ophthalmology, especially glaucoma, and lasers are slowly replacing many glaucoma surgeries. Conventional trabeculectomy has so far remained the gold standard for glaucoma surgery and efforts are being made to develop a new surgical approach to overcome the limited success rate and safety issues of this traditional procedure. There is a great interest in using lasers for ab interno and ab externo penetrating and nonpenetrating filtering surgery. Theoretically, laser-assisted surgery offers the potential advantage of improved accuracy, repeatability, and safety, although the main drawback of using lasers for this purpose is the potential collateral damage induced by the scattered energy. Collateral thermal damage adjacent to the sclerostomy site is believed to be detrimental to the long-term success of the filtering procedure. Employing a laser with high water absorbance and low light scattering reduces the extent of collateral thermal damage and improves the long-term surgical success. An increasing number of different radiation sources have been examined for penetrating and nonpenetrating glaucoma surgery with various success rates.