Although a considerable body of research has been developed in recent years on participation in adult education, little has been done from the standpoint of social policy and its impact on participation. To assist investigation of this aspect of participation, three social policy models are presented: market models, progressive-liberal-welfare models, and social control models. The models can be linked to three adult education streams of practice: the vocational, liberal/liberatory, and social reconstruction streams. They can also be linked to sociological theories on a continuum from structural functionalism to conflict theory. A taxonomy of mechanisms found in policy within each social policy model is proposed, and a number of participation research issues for future investigation on this issue are suggested. (Author/KC)