The paper aims to contribute to theory on collaboration through problematizing and exploring the complexity that characterizes leadership in collaborative contexts and to provide some generative conceptualizations to inform future empirical and conceptual development. It draws on a substantial review of leadership theory relevant to the context of public sector collaboration and provides examples from empirical research on collaboration over the last two decades in the UK and US respectively. It does so by identifying and developing key characteristics of the context, the nature of leadership in relation to context, and leadership agency pertaining to actors who actually make a difference in the process and outcomes of collaboration
