The topic of indoctrination is relevant to educational theory and philosophy as it is widely viewed as an unacceptable process that is the antithesis of education. Knowing the features of indoctrination will enable educators to guard against any extreme ideology that could undermine their students’ cognitive, affective, and behavioral development, and it also enables them to avoid using indoctrinatory techniques in their own classrooms. This entry briefly discusses the evolution of thinking about indoctrination; the concepts of indoctrination, an indoctrinated person, and indoctrinatory tradition; and the fundamental differences between indoctrination, enculturation, and brainwashing.