Objective <p>This systematic review evaluates the effectiveness and safety of intra-articular injections for temporomandibular joint (TMJ) arthralgia in adults, comparing various injection types against alternative treatments or placebo.</p> Methods <p>We conducted a comprehensive literature search across Scopus and Pubmed from January 2015 to December 2024, including randomized controlled trials, prospective comparative clinical trials, and observational studies with control groups. Eligibility criteria required adult patients with clinically diagnosed TMJ arthralgia, various intra-articular injections, and outcome measures including pain reduction and jaw function improvement. The Cochrane Risk of Bias Tool (RoB 2) assessed methodological quality across included studies.</p> Results <p>The review included seven high-quality studies with sample sizes ranging from 20 to 114 participants across multiple countries. All injection types—corticosteroids, hyaluronic acid, and platelet-rich plasma—demonstrated significant pain reduction and functional improvement within treatment groups. Between-group differences were often not statistically significant in high-quality randomized controlled trials. Specific advantages were noted: sodium hyaluronate may be more effective for reducing joint noises, while corticosteroids showed better short-term pain relief.</p> Conclusion <p>The evidence supports intra-articular injections as effective treatment options for TMJ arthralgia, though no single intervention consistently outperformed others across all outcomes. Treatment selection should be individualized based on patient presentation and preferences.</p> Other <p>This review was prospectively registered in PROSPERO (CRD42025632073) and received no external funding.</p>