Pessaries are an important conservative therapy for stress urinary incontinence (SUI), but few studies have comprehensively evaluated their utility. The objective of this study is to evaluate the existing evidence on the efficacy and safety of pessaries for the treatment of SUI. We searched for the terms "stress urinary incontinence" and "pessar/y/ies/ium" in PubMed, Embase, and Cinhal on June 10, 2020. Studies that characterized subjective and/or objective data were included. Studies performed in pediatric populations, pregnancy, and use of pessaries not for SUI were excluded. Two reviewers independently screened and assessed data quality and risk of bias according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Ten studies, including 376 patients, were included. In terms of subjective outcomes, 76% of 72 patients reported feeling continent after pessary treatment compared with 0% of 86 patients surveyed before pessary use (P < 0.0001). Both Urinary Distress Inventory and Incontinence Impact Questionnaire scores decreased significantly by 46.7% (n = 155 baseline, n = 139 follow-up; P < 0.0001) and 67.8% (n = 139 baseline, n = 107 follow-up; P < 0.0001), respectively. Significant objective measures associated with pessary use included increased urethral closure pressure (n = 122; g = 0.56; 95% confidence interval [CI], -0.66 to 1.77; P < 0.049) and decreased pad weight (n = 129 baseline; n = 118 follow-up; g = -0.89; 95% CI, -1.986 to 0.19; P = 0.009). Adverse events significantly decreased at greater than 6 months follow-up compared with less than 6 months follow-up, including pain (31.5%, n = 29/92 vs 14.3%, n = 5/35; P = 0.0513) and discomfort (50%, n = 46/92 vs 29.3%, n = 12/41; P = 0.0268). Based on both subjective and objective measures, pessaries are an effective conservative treatment option for SUI. This supports pessary use, though larger studies with longer-term follow-up are warranted.