Background: Double-row rotator cuff repair is often used to improve tendon healing. However, its effect on clinical outcomes is still not clearly established. Methods: A systematic review and meta-analysis was performed following PRISMA guidelines. This study compared single-row and double-row repair. Structural integrity and functional outcomes were evaluated. Structural failure was defined as any non-intact repair, including both partial- and full-thickness defects. Odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated using a random-effects model. Results: Eight comparative studies were included. Six contributed to structural analysis, and six reported functional outcomes. Among these, four were included in the quantitative synthesis for functional results. Structural failure occurred in 42.7% of shoulders after single-row repair and 26.4% after double-row repair. This corresponds to an absolute reduction of about 16%, which is significant in practice. Double-row repair reduced the risk of structural failure (OR 0.47, 95% CI 0.29 to 0.75; I² = 0%). In contrast, postoperative Constant scores were similar between groups (MD −0.08, 95% CI −3.98 to 3.82; I² = 0%). Conclusion: Double-row repair improves structural integrity. But it does not seem to improve functional outcomes, at least within the current sample size. This indicates that structural healing and clinical recovery may not fully align.