This essay provides a detailed comparison of two prominent nursing theories: Peplau's theory of interpersonal relations and Parse's theory of human becoming. It delves into the background, philosophical underpinnings, and clinical applications of each theory. Peplau's theory focuses on the relationship between the nurse and the patient, emphasizing communication and a patient-centered approach, while Parse's theory emphasizes the patient's quality of life and individual dignity. The essay explores the four phases of Peplau's theory (orientation, identification, exploitation, and termination) and the three principles of Parse's theory (meaning, rhythmicity, and transcendence). It also compares the theories within the context of nursing practice, highlighting their differences and similarities in guiding nursing practice and enhancing patient care. The conclusion emphasizes the importance of both theories in improving nursing practice and patient outcomes.