Over the last decade, it has become increasingly recognised that school leadership is critical for improved student outcomes. Hence, the spotlight is on leadership of teaching and learning, not only the learning of students, but also of professionals. Traditionally, leadership in schools has been associated with positional authority; the province of the principal. In recent years, it has been acknowledged that the capabilities of a single individual are inadequate for the many leadership roles and tasks in schools, including the challenge of preparing a diverse group of students for success in a post-industrial, knowledge-based world. Rather than associating leadership solely with the school principal, leadership is now also thought of as being distributed throughout the organisation across many talented actors (Gronn, 2002; Spillane, 2001; 2004). In addition to leading as individuals with responsibility and accountability for improving student outcomes, collaborating in subject teams is seen as a progressive way to lead teaching and learning. Subject teams are perceived to serve the function of learning communities where professionals collaborate and engage in dialogue about improving teaching and learning. One form of dialogue is advice and information – the building blocks of knowledge (Spillane, Healey, & Kim, 2010). Such knowledge is shared, not only in formal contexts, but also through informal networks; and is provided not only by formal leaders, but also by informal teacher leaders, as this study found.