Teachers in Hong Kong have faced constant demand for practice renewal due to successive waves of educational reforms in the past decade. This paper describes the design of an assignment structure that promotes teacher reflection on important issues related to a major education reform in Hong Kong. This particular assignment structure includes three components--self-reflection, understanding alternative perspectives and situated analysis. Teachers are expected to complete these components in a sequence. The design addresses teachers' teaching experiences, engages them in learning alternative perspectives, and assists them to juxtapose self-reflection and alternative perspectives in analysing commonly encountered teaching situations. An evaluation of teachers' levels of reflection in these assignments showed that both high- and low-scored teachers improved their reflection. Based on the findings of an interview study, this paper reported a grounded model explaining how this innovative assignment structure promotes reflection. The model situated the reflective assignments within the local teaching context in Hong Kong and highlighted the importance of different forms of assistance and guidance in facilitating teachers' reflective engagement in completing these cognitively demanding assignments. (Contains 2 tables and 1 figure.)