|While much of contemporary educational leadership scholarship focuses on formal leadership (that exercised through officially designated roles in schools and school systems), leadership exercised informally is an increasing focus of theorists in instructional leadership, distributed leadership, and teacher leadership, as well as practitioners. Research has insufficiently probed how informal leaders function in schools, particularly through interactions with colleagues. This study uses a mixed methods social network research approach, combining quantitative social network analysis with qualitative study informed by social network theory, to understand informal leadership at an elementary school. All staff were surveyed regarding whom they turned to for various types of advice, information, and support; these questions produced three network diagrams used to select informal leaders for the qualitative stage. Qualitatively, three teachers leading informally were interviewed, observed, and asked to complete logs of their conversations; key teachers connected to informal leaders were also interviewed. Network analyses reveal similar highly ranked individuals across all three networks, though their leadership is exercised through different interpersonal relationships. Qualitative data focused on the interest of informal leaders in developing solutions to specific instructional issues, rather than enforcing a broad instructional vision. I propose three prerequisites to an informal leadership interaction: the vision for improved instruction of the informal leader, the presence of an instructional variation in the informal leader’s own practice, and an invitation from a colleague to offer advice, information, or support on a specific instructional issue. These findings advance distributed leadership’s consideration of how leadership is situated by particular contexts, and suggests the importance of certain leadership tools, including modeling teaching and the use of instructional technologies. Future questions and recommendations reiterate the need for work on leadership practiced informally, and suggest consideration of the contexts in which leadership interactions take place.