The biomechanics of clear aligners plays a crucial role in determining the efficiency, predictability, and success of orthodontic tooth movement during aligner therapy. Clear aligners utilize controlled and sequential application of forces generated through customized thermoplastic appliances to achieve desired dental movements. Unlike conventional fixed orthodontic systems, aligners deliver intermittent forces through intimate adaptation to the tooth surfaces and programmed activation within digital treatment setups. The biomechanics involved in clear aligner therapy are influenced by factors such as aligner material properties, thickness, fit, attachment design, staging of tooth movement, and patient compliance. Different types of tooth movements—including tipping, bodily movement, rotation, intrusion, extrusion, and torque control—require specific biomechanical considerations and auxiliary features such as attachments, pressure points, and elastics to enhance force delivery and anchorage control. Advances in digital orthodontics and finite element analysis have improved understanding of stress distribution, force systems, and aligner behavior during treatment. Although clear aligners provide aesthetic and comfortable orthodontic treatment, limitations remain in achieving complex tooth movements with absolute predictability. This topic highlights the fundamental principles, force mechanics, clinical applications, limitations, and recent innovations associated with the biomechanics of clear aligners in modern orthodontic practice.