PURPOSE: To determine if metformin is associated with noninfectious uveitis (NIU). METHODS: Patients in an insurance claims database who initiated metformin (n = 359,139) or other oral anti-diabetic medications (n = 162,847) were followed for NIU development. Both cohort and case-control analyses were performed to assess differing exposure lengths using Cox and conditional logistic regression, respectively. RESULTS: The hazard ratio (HR) for incident NIU was not significantly different between the metformin and non-metformin cohorts [HR = 1.19, 95% Confidence Interval (CI): 0.92-1.54, = .19]. The case control analysis similarly showed no association between any metformin use 2 years before the outcome date and NIU [odds ratio (OR) = 0.64, 95% CI: 0.39-1.04, = .07]. However, there was a protective 20 association between cumulative metformin duration [(445-729 days) adjusted OR (aOR) = 0.49, 95% CI: 0.27-0.90, = .02] and dosage (>390,000 mg aOR = 0.44, 95% CI: 0.25-0.78, = .001) compared with no metformin use. CONCLUSIONS: Our results suggest metformin use for longer durations may be protective of NIU onset.