Web-based staff development may be able to overcome some of the problems inherent in ‘traditional’ staff development. Teachers, as learners, can work at their own pace, in private if they wish, and material can be covered in a just-in-time fashion targeting the exact need. However, online instruction has the potential to be as ineffective as other poor forms of instruction. With this in mind, a web-based staff development module was developed at the University of Western Sydney based on constructivist learning principles. This paper looks at the rationale for web-based staff development, how constructivist principles were applied in practice and preliminary findings from research into the use of the online module developed.