Arguments regarding the distinction between child and adult learning have existed for decades. Pedagogy has a long tradition of providing educational guidance in which there is little differentiation between child and adult education. The two groups of learners are assumed to learn under the same philosophy. Conversely, andragogy, advanced by Malcolm Knowles in the 1970s, is a well-known approach to address the distinct needs of adult learners. Knowles' concept of andragogy has been widely adopted by educators from various disciplines around the world. Andragogy is based upon six assumptions: (a) self-directedness, (b) need to know, (c) use of experience in learning, (d) readiness to learn, (e) orientation to learning, and (f) internal motivation. This paper presented a synthesis of research that discussed the applications of Knowles' andragogy in different settings.