Study Design: Systematic literature review. Objective: To assess the efficacy of deep friction massage (DFM) in the treatment of tendinopathy. Context: Anecdotal evidence supports the efficacy of DFM for the treatment of tendinopathy. An advanced understanding of the etiopathogenesis of tendinopathy and the resultant paradigm shift away from an active inflammatory model has taken place since the popularization of the DFM technique by Cyriax for the treatment of "tendinitis." However, increasing mechanical load to the tendinopathic tissue, as well as reducing molecular cross-linking during the healing process via transverse massage, offers a plausible explanation for observed responses in light of the contemporary understanding of tendinopathy. Evidence Acquisition: The authors surveyed research articles in all languages by searching PubMed, Scopus, Pedro, CINAHL, PsycINFO, and the Cochrane Library using the terms deep friction massage, deep tissue massage, deep transverse massage, Cyriax, soft tissue mobilization, soft tissue mobilisation, cross friction massage, and transverse friction massage. They included 4 randomized comparison trials, 3 at the extensor carpi radialis brevis (ECRB) and 1 supraspinatus outlet tendinopathy; 2 nonrandomized comparison trials, both receiving DFM at the ECRB; and 3 prospective noncomparison trials-supraspinatus, ECRB, and Achilles tendons. Articles meeting inclusion criteria were assessed based on PEDro and Centre for Evidence-Based Medicine rating scales. Results: Nine studies met the inclusion criteria. Evidence Synthesis: The heterogeneity of dependent measures did not allow for meta-analysis. Conclusion: The varied locations, study designs, etiopathogenesis, and outcome tools used to examine the efficacy of DFM make a unified conclusion tenuous. There is some evidence of benefit at the elbow in combination with a Mills manipulation, as well as for supraspinatus tendinopathy in the presence of outlet impingement and along with joint mobilization. The examination of DFM as a single modality of treatment in comparison with other methods and control has not been undertaken, so its isolated efficacy has not been established. Excellent anecdotal evidence remains along with a rationale for its use that fits the current understanding of tendinopathy.