Despite extended and substantial clinical experience with laser trabeculoplasty, it is used relatively infrequently. Reasons include associated significant tissue disruption with consequent reluctance from re-treatment, lack of full understanding of the mechanism by which intraocular pressure (IOP) is reduced, and known complications. Selective laser trabeculoplasty results in selective absorption of energy by trabecular pigmented cells, sparing adjacent cells and tissues from thermal damage. Morphologic studies demonstrated minimal tissue alteration following treatment with selective laser trabeculoplasty. Clinical studies suggest it is efficacious in lowering IOP, as initial treatment or when medical therapy is insufficient, with response rates after 1 year ranging from 59% to 96%. Average reduction in IOP has been reported from 18% to 40%. Comparative studies suggested similar IOP reduction by argon laser trabeculoplasty and selective laser trabeculoplasty. Observed side effects have been mostly transient and minor. We review the current knowledge of the mechanisms and clinical outcome of selective laser trabeculoplasty.