Given its importance and value in ensuring quality education, the Continuing Professional Development (CPD) of teachers draws significant attention from researchers. Research has thus focused on teachers' CPD practices and the factors influencing those practices. However, a broad theoretical framework that relates teacher CPD participation factors to teacher characteristics and explains their interaction and the resultant CPD practices is yet to be developed. To address this gap, this article reviews literature on teacher CPD and synthesizes an empirically testable theoretical framework. The article begins by adopting a wide definition of teacher CPD as all learning that teachers undertake to improve their professional competencies, and proceeds to identify the essential aspects of teacher CPD and the factors that influence teachers' participation in CPD. An analysis of the literature leads to the conclusion that teacher CPD is a context bound and goal-oriented learning activity, characterized by multiple aims, content, learning methods. By viewing teachers as adult learners and rational choice takers, principles of Adult Education Theory and propositions of the Rational Choice Theory are then used to explain the interaction of the factors and observed CPD practices. The article concludes by presenting several hypotheses and methodological implications arising from the framework.