• This study investigates the usability and user acceptance of biometric authentication across different applications, including mobile devices and smartphones, access control systems, banking and financial applications, healthcare systems, and travel and border control. The research aims to identify the factors that influence user acceptance and the potential challenges faced in each domain. The findings reveal that biometric authentication in mobile devices and smartphones is widely accepted due to its convenience and speed. However, concerns related to false acceptance or rejection rates, sensor accuracy, and privacy issues can affect user acceptance. Similarly, in access control systems, fast and reliable biometric systems with seamless user experiences are more likely to be accepted. Challenges such as long verification times, high false rejection rates, and complex enrollment processes can impact user acceptance negatively. In banking and financial applications, user acceptance depends on the perceived security and privacy of biometric data. Trust in the system, a user-friendly interface, and clear instructions are crucial factors influencing user acceptance. Healthcare systems face unique challenges, including hygiene concerns, ease of use for elderly or disabled patients, and adherence to privacy and security regulations. User acceptance in healthcare settings is influenced by these factors, along with overall system reliability. In travel and border control, biometric authentication, particularly facial recognition, is gaining popularity for identity verification and immigration processes. User acceptance is influenced by factors such as accuracy, speed, and perceived effectiveness in enhancing security and reducing queues. Privacy concerns and data protection policies also play a role in shaping user acceptance.