A meta-analysis examined the effect of obesity or being overweight on the risk of glaucoma, the leading cause of vision loss. A systematic search was conducted in PubMed, Embase and Web of Science databases until March 24, 2025 and included 13 studies. Obese or overweight subjects had a 60% higher risk of glaucoma compared to those of normal weight (OR: 1.60 [95% CI: 1.19–2.17], p = 0.002). In developed countries, the risk was 91% higher (OR: 1.91 [95% CI: 1.44–2.52], p < 0.001). In obese or overweight men, the risk was increased by 114% (OR: 2.14 [95% CI: 1.24–3.69], p = 0.006). Studies assessed clinical outcomes using odds ratios (OR) or hazard ratios (HR) with 95% confidence intervals and quality according to an eight-item scale. The conclusion states that maintaining a normal weight can be an effective measure to prevent glaucoma.