This exploratory study presents an examination of the relationships between and among teacher leadership and social, material, and human resources. This study answers the following research questions: How does active teacher leadership influence a school's human resources, in terms of reported changes in teaching practice? What is the relationship between a school's social and material resources and its implementation of teacher leadership? Findings indicate that teacher leaders engage in two types of functions - support and developmental. Which functions teacher leaders are able to engage in is determined by their access to contextual social and material resources; these resources include support from administrators, relationships with colleagues, time to enact the teacher leader role, and involvement in professional development. This study establishes that teacher leadership positively influences a school's human resources when these contextual factors allow for teacher leaders to engage in developmental functions. Therefore, social and material resources impact whether or not teacher leaders can improve teaching practice.