Distributed leadership has been the subject of considerable educational research and discourse in recent years. This thesis explores how it is understood in the Irish post primary school context, with particular reference to its impact on teaching and learning. A study of distributed leadership is particularly timely, as a number of international studies have highlighted the need for leadership to be distributed throughout the organisation with a view to improving student outcomes. Following a preliminary study in one school, the research focused on a study of three schools. As the issues emerged, it became evident that by moving beyond case study to cross-school participation there would be a richer dialogue, participants would learn from each other and impetus would be created for further action. Therefore, three different crossschool focus group discussions were held: one with principals and deputy principals, one with teachers holding posts of responsibility and one with teachers not holding posts of responsibility. Although holding very different positions of leadership in their schools, principals, deputy principals and teachers shared a common understanding of distributed leadership. The term was understood to incorporate four dimensions: leadership roles (which may be formal or informal), individual traits (particularly those related to influencing others), having a sense of belonging to the school organisation and supporting the development of leadership capacity in individuals. While this study revealed that in general, teachers in each of the three schools perceive distributed leadership to be necessary and positive, this is not always matched by their experience of leadership practices. Principals acknowledged their role in leading learning and in developing leadership capacity among teachers. They highlighted two key areas: a more intentional focus on teaching and learning within the post of responsibility and subject department structures; and the development of individual leadership skills and talents among teachers. These provide opportunities for the exercise of leadership in informal as well as formal roles and actions. Participation in this study was part of a journey of leadership development in each school and is a stepping stone to further action. This research points to the usefulness of distributed leadership as a lens to analyse teaching and learning and presents hypotheses on leadership practices that could form the basis for empirical research.