Mucoadhesive buccal films are an innovative transmucosal drug delivery system that significantly overcomes the limitations of conventional oral dosage forms, such as extensive first-pass hepatic metabolism and enzymatic drug degradation, by enabling direct systemic absorption through the highly vascularized buccal mucosa. Constructed from carefully selected natural, synthetic, or semi-synthetic polymers and formulated with permeation enhancers, plasticizers, and taste-masking agents, these flexible films can deliver a wide spectrum of drugs, including small molecules, peptides, and proteins, for local or systemic therapeutic action, offering rapid onset, improved bioavailability, and enhanced patient compliance particularly in pediatric, geriatric and emergency settings. Recent advances in polymer science, nanotechnology, and fabrication technologies, such as 3D printing, have expanded their application range, although key challenges remain in maximizing drug payload, large-scale production, and regulatory standardization; ongoing research prioritizes patient-centric innovation in clinical and commercial translation of buccal films as a future pillar of personalized medicine.