For the last decade, our government has initiated a series of site-based educational reform movements, which has brought about dramatic changes in school administration and curriculum. In response to reform efforts, teachers ought to adjust themselves to the change process in which the role of teachers has shifted from a passive follower to an active leader of change at both instructional and management levels. Teacher leaders are able to improve teaching and learning practices by being involved in different levels of development in schools. The purpose of this article is to explore teachers' roles in shaping collaboration culture of school organizations from the perspective of teacher leadership. Mainly included are three sections, first, the history, theory, and practices of teacher leadership, which describes the developmental stages of teacher leadership, a variety of leadership theories related to teacher leadership, definitions of teacher leadership, and what teacher leaders actually do. The second section explores theory and empirical research on collaboration culture of school organizations that manifests types of school collaboration culture and the effects of collaboration culture on school effectiveness. Finally, concluding from the first two sections, what teacher leaders should do in re- or constructing school collaboration culture are transforming school structures, building consensus, facilitating the dialogues between administrators and teachers, and establishing connections to school communities. The applications of teacher leadership to schools in Taiwan are discussed in regards to the roles teachers play in the change process and the problems that might emerge due to the specific context in Taiwan's educational system.