Many schools are organised into departments which function as contexts that frame teachers' professional experiences in important ways. Some educational systems have adopted distributed forms of leadership within schools that rely strongly on the departmental structure and on the role of the department coordinator as teacher leader. This paper reports a study of department networks and distributed leadership in two schools. The study collected two types of data on teacher networks in the schools: attributions of the influence of colleagues on one another's professional development and joint professional practice. Measures included actor centrality and network density. The study identified distinct leadership configurations in different departments. The implications for the study of distributed leadership and for the distribution of leadership roles in educational organisations are discussed. (Contains 2 tables, 4 sociograms and 4 notes.)