The profession of nursing continues to struggle with defining and clarifying its professional identity. The definitive recognition of nursing as a profession was the moving of training from the hospital apprentice model to the tertiary sector. However, this is only part of the story of professional identity in nursing. Once training finishes and enculturation into the workplace commences, professional identity becomes a complicated social activity. This paper proposes social identity theory as a valuable research framework to assist with clarifying and describing the professional identity of nurses. The paper outlines the key elements of a profession and then goes on to describe the main concepts of social identity theory. Lastly, a connection is made between the usefulness of using social identity theory in researching professional identity in nursing, recognizing the contextual nature of the social activity of the profession within its workplace environment.