This paper considers several trends in professional development programmes found internationally. The use of multiple learning approaches and of different modes and types of learning in PD is described. Various theories and models of evaluation are discussed in the light of common professional development activities. Several recommendations are made to progress matters and links made with school and leadership effectiveness issues. A theoretical framework for empirical research and evaluation is posited with a plea for more research in this field, especially outside North America. (Contains 3 figures.)