Abstract Background Rotator cuff tears (RCTs) are a leading source of chronic and acute shoulder pain globally, with causes spanning from tendon degeneration to traumatic injury. Especially prevalent in the aging population, RCTs have a significant retear rate despite surgical intervention, and recent years have seen an increase in the use of grafts in surgery to address many of the clinical issues previously encountered in tendon-healing. Objectives To compare the effectiveness of various grafts in graft-augmentation surgery for full-thickness rotator cuff tears, assessed with functional and clinical outcomes. Selection criteria Adult patients with MRI-diagnosed full-thickness RCT and subsequently underwent graft-augmentation surgery; followed-up >1year, with assessment for retear and quantitative clinical outcomes. Results 32 primary studies, mean follow-up of 2 years and total of 1052 patients were included. The effectiveness of graft-augmentation was assessed using retear rate, ASES, Constant, UCLA and VAS. Graft-augmentation significantly improves all functional and clinical scores (p<0.05), and decreases retear rate to an average of 18.5% >1year post-surgery (p<0.0001), with no significant difference in effectiveness between the 4 different types of grafts. (p>0.05). No significant difference in outcomes was found in graft-augmentation between different tear sizes. Conclusions Graft augmentation for RCTs shows significant improvements in clinical and functional outcomes, and significantly lowers retear rate compared to conservative treatment or surgery without graft augmentation. The choice of graft has been shown to be of less importance than the clinical decision to use surgical-intervention with graft-augmentation, which applies to full-thickness tears of all sizes; both primary and revision tears.