The purpose of this study was to determine the factors associated with the outcomes of selective laser trabeculoplasty (SLT). This was a database analysis (Lausanne Laser Trabeculoplasty Registry) of patients who had SLT between 2015 and 2017. Exclusion criteria were age below 40 years and diagnosis other than ocular hypertension and open-angle glaucoma. Intraocular pressure (IOP) and number of medications were recorded before and at various follow-ups after laser treatment. Success was defined as "complete" if an IOP reduction of at least 20% was observed at a given time, and "qualified" if any reduction of IOP was observed with either at least a 20% difference from baseline or a reduction in IOP-lowering medications. Associations of complete and qualified success with patients' baseline characteristics, laser settings, and clinical examination findings were studied using multivariate regression and survival analysis. A total of 170 eyes (126 patients) were included. Mean age was 68.3±12.2 years and 57.9% of the study cohort were female individuals. Average baseline IOP was 18.7±4.8 mm Hg, and average IOP reduction was 3.3±4.3 (-17.6% from baseline) and 3.5±3.9 mm Hg (-18.7% from baseline) at years 1 and 2, respectively. Male sex [odds ratio (OR)=2.79, P=0.02], baseline IOP (OR=1.15, P<0.01), and medical treatment before SLT (OR=2.57, P=0.03) were positive predictors of success. Total energy was associated with the duration of success. SLT outcome was strongly correlated to the outcome of the fellow eye, which represented the strongest predictor (OR=17.33, P<0.01). SLT achieved good IOP-lowering in a majority of patients with mild-to-moderate glaucoma, while it was inefficient in up to 35% of eyes. SLT success in the fellow eye was a strong predictive factor.