The present study focuses on the development and evaluation of a controlled-release buprenorphine buccal film to enhance bioavailability, ensure sustained therapeutic effect, and improve patient compliance. Buccal films were prepared using various hydrophilic and mucoadhesive polymers via the solvent casting method, incorporating suitable plasticizers to achieve flexibility and uniformity. Formulations were evaluated for physical characteristics, including thickness, weight uniformity, surface pH, and drug content, all of which met pharmacopeial standards. In vitro drug release studies demonstrated sustained release over 8 hours, with the optimized formulation (F6) achieving approximately 97.85% cumulative release, following diffusion-controlled kinetics with a contribution from matrix erosion. Kinetic modeling indicated compatibility with Higuchi and first-order release models, confirming controlled release behavior. Stability studies under various temperature and humidity conditions (25°C/60% RH, 30°C/75% RH, 40°C/75% RH) revealed no significant changes in physical properties or drug release over 90 days, highlighting the formulation's robustness. Overall, the developed buprenorphine buccal film demonstrates a safe, stable, and patient-friendly platform for sustained drug delivery, offering potential advantages over conventional oral dosage forms in pain management and opioid therapy.