Adult education is the practice of teaching and educating adults. Adult education takes place in the workplace, through 'extension' school (e.g. Harvard Extension) or 'school of continuing education' (Columbia School of Continuing Education). Other learning places include community colleges, folk high schools, and lifelong learning centers. The practice is also often referred to as 'Training and Development 'and is often associated with workforce or professional development. It has also been referred to as andragogy (to distinguish it from pedagogy). Adult education is different from vocational education, which is mostly workplace-based for skill improvement; and also from non-formal adult education, including learning skills or learning for personal development.

In 1926 the American Library Association study Libraries and Adult Education was published and the association established the Board on Library and Adult Education (later the Adult Education Board) with reports in the ALA Bulletin. The concept of the library as an agency of ongoing education for adults became firmly established in U.S. society. In her historical review of libraries and adult education, Margaret E. Monroe (1963: 6) identified a variety of library services provided by libraries to adults during the first half of the twentieth century that incorporated aspects of adult education. Many libraries have a literacy center, either within their community or in the building; others offer on-site tutoring for adults, or at least space for tutors to meet with students. Family literacy programs are also quite popular within libraries and schools. Roehrig, L. (2010). The U.S. Institute of Museum and Library Services helps create vibrant, energized learning communities recognizing that "Our achievement as individuals and our success as a democratic society depends on learning continually, adapting to change readily, and evaluating information critically."