Internal derangement of the temporomandibular joint (TMJ) is a common condition causing pain and dysfunction. Arthrocentesis with intra-articular injection of hyaluronic acid (HA) and corticosteroid has been proposed as a treatment modality, yet its efficacy remains debated. Materials and Methods: A prospective study was conducted on 50 patients diagnosed with internal derangement of the TMJ. All patients underwent arthrocentesis with intra-articular injection of HA and corticosteroid. Pain levels were assessed using a visual analog scale (VAS), and maximum interincisal opening (MIO) was measured before and after the procedure. Data were analyzed using paired t-tests. Results: Following the intervention, there was a significant reduction in pain levels, with the mean VAS score decreasing from 7.2 ± 1.5 to 3.4 ± 1.2 (p < 0.001). Additionally, there was a notable improvement in MIO, increasing from 32.5 ± 4.8 mm to 40.2 ± 5.6 mm (p < 0.001). Conclusion: Arthrocentesis with intra-articular injection of HA and corticosteroid appears to be an effective treatment modality for internal derangement of the TMJ, resulting in significant pain reduction and improved jaw function. Further long-term studies are warranted to validate these findings and assess the sustainability of outcomes