The philosophy of radical behaviourism remains misunderstood within the field of adult education. Contributing to this trend is the field's homogeneous behaviourist interpretation, which attributes methodological behaviourism's principles to radical behaviourism. The guiding principles and assumptions of radical behaviourism are examined to highlight distinctions between the two philosophies. Significant differences are found in positions on private events, reductionism, mechanism, operationalism, and logical positivism. Examples of critical misunderstandings in adult education literature are detailed. The philosophy's impact on adult education is discussed in three areas: instructional design, adult career and technical education, and human resource development. Recent advances in behaviour analytic research and practice are then presented to demonstrate its continued relevance to adult education. It is argued that a re-conceptualization of behaviourism is needed to position radical behaviourism as a unique adult education philosophy.