Sense of belonging is a concept that has not been researched in psychiatric nursing practice. Using a concept-analysis strategy proposed by Walker and Avant, the authors present a detailed description of the concept that evolved from a series of inductive and deductive strategies. Sense of belonging is defined as the experience of personal involvement in a system or environment so that persons feel themselves to be an integral part of that system or environment. Sense of belonging has important applicability for clinical use as well as continued theory development in psychiatric nursing.