Background: Adhesive capsulitis, or frozen shoulder, is a debilitating condition characterized by pain, restricted range of motion, and functional limitations. Thoracic spine dysfunction is increasingly recognized as a contributing factor to impaired shoulder mechanics. Objective: To systematically review the effectiveness of thoracic mobilization in improving pain, range of motion, and function in individuals with adhesive capsulitis. Methods: A systematic search was conducted across PubMed, Scopus, and Google Scholar. Studies involving thoracic mobilization interventions for adhesive capsulitis were selected based on predefined inclusion and exclusion criteria. Data regarding pain, range of motion (ROM), and functional outcomes were extracted and analyzed. Results: Six studies met the inclusion criteria. The findings consistently demonstrated that thoracic mobilization, when combined with conventional therapy, resulted in significant improvements in pain reduction, shoulder ROM, and functional disability scores. Conclusion: Thoracic mobilization is an effective adjunctive therapy for adhesive capsulitis, improving pain, mobility, and functional outcomes. Further high-quality randomized controlled trials are recommended.