Simulation and game-based learning are educational strategies that are grounded in adult learning theory. Adult learners differ from young learners in many ways. Instructors must recognize these differences and tailor their instructional strategies accordingly. While there are many theories of adult learning, no single theory fully explains how and why adults learn through simulation-based methods. This chapter introduces adult learning theories that have been described in the context of simulation education and how the awareness of these concepts can be applied to simulation curriculum development, implementation, and assessment in health professional learners.