Simulation is often used in nursing education as a teaching methodology. Simulation is rooted in adult learning theory. Three learning theories, cognitive, social, and constructivist, explain how learners gain knowledge with simulation experiences. This article takes an in-depth look at each of these three theories as each relates to simulation. Pedagogical approaches as well as ties to simulation of each theory are addressed. Finally, the implications for research and practice in health care and adult education are discussed.