The ability to state with confidence that coaching is underpinned by a robust evidence-base is central to any claims that coaching is an effective and credible intervention. The type and quality of the research upon which our evidence is based is, vital to both the knowledge that informs the discipline and secure the future of coaching. Yet evidence is always partial and open to interpretation. Moreover, it serves an increasingly complex range of functions for an increasingly diverse range of stakeholders. These realities give rise to a variety of ethical issues. This chapter examines some of the ethical issues arising from attempting to grow the evidence-base of coaching. The chapter explores what is meant by evidence, the lack of synergy that can occur between research and practice and how any evidence sought will vary as a function of the underlying philosophical perspective adopted. The responsibilities of coaches as producers and consumers of knowledge are also considered with a framework for navigating the ethical complexities encountered in research provided. In exploring these issues the aim is to contribute new questions to help us consider what is needed for coaching to move confidently and ethically towards its claim of being an evidence-based profession.