This chapter describes the principles of adult learning. The field of adult learning was introduced by Malcolm Knowles. It is a new area of study which involves understanding how adult learns best compared to children and teens team. According to Ernert Baker, adult education is a course to be taken up concurrently with work and the earning of living. It is to be given on part-time basis. The purposes of adult education are individual’s point of view and social point of view. Need and importance of adult education, organization of adult education, scope of adult learning, characteristics of adult learning, methods of teaching adults, agencies of adult education, and problems of adult education are also covered in this chapter.