This article presents the results of an evaluation study in Physical Education (PE) in which 23 schools, 49 classes and 1142 year 4 Cypriot students participated. This study attempted to identify the extent to which a theoretical framework of educational effectiveness research based on Creemers' model can be developed. The relationship between generic and differentiated effectiveness was also examined. Most of the variables in Creemers' model showed the expected effects, irrespective of the criterion used to measure effectiveness in PE. The great majority of teachers were found to be equally effective in achieving different aims of PE. There was some variability in the effectiveness status of most teachers who were expected to teach PE in classrooms of different schools. Implications of findings for the development of generic and differentiated models of educational effectiveness are drawn. (Contains 3 tables.)