This report provides a detailed comparison of Henderson's Theory of Self-Efficacy and Roy's Adaptation Model. It begins with an overview of each theory, including their core concepts, philosophical underpinnings, and assumptions. The report explores the background of each theory, discussing their origins and key components. It then delves into the clinical applications of both theories, providing specific examples of how they can be utilized in various healthcare settings, such as in the care of cancer patients and those with aortic valve diseases. The similarities and differences between the two theories are highlighted, focusing on their approaches to patient care and the roles of nurses. The report emphasizes the importance of these theories in nursing practice, the application of these theories in various clinical settings, and the role of nurses in ensuring quality patient care. The report also includes an introduction to the theories, their background, philosophical underpinnings, and clinical applications, along with a comparison of their use in nursing practice.