This article examines the design of a professional development model that aims to improve student achievement. This model has been designed by combining and supplementing elements from school-improvement literature and existing professional development models. Existing models from two largely independent approaches to professional development of teachers were examined for the presence of nine principles for effective school improvement. On the basis of this examination six aspects from the existing models were incorporated in the new model (presentation of theory, demonstration of skills, practice in a secure environment, pre-conference, observation and post-conference). Three further aspects were added to ensure compliance with all nine principles for effective school improvement (creation of the appropriate conditions, evaluation and monitoring conference and a focus on goals at school, teacher and student level). (Contains 1 figure and 2 tables.)