Organisations that use coaching programmes express their need for the assessment of coaches to ensure quality of provision. One solution to this need has been provided by professional bodies that assess coaches as part of their accreditation systems, often using competency frameworks. In this conceptual paper we open four specific debates in order to explore inherent problems associated with this approach. We start by highlighting the divide that seems to be emerging in coaching between academia and the professional bodies. We then move on to discuss the degree to which the gradation of coaching expertise in assessment is justified. The third debate concerns the extent to which competency frameworks are appropriate for coach assessment. Lastly, we question whether the existing paradigms, on which many assessment systems are based, effectively represent the coaching interaction. We argue that by seeing the coaching engagement as a complex adaptive system, a different conceptual approach to the assessment of coaches is needed, one that focuses on capabilities rather than competencies alone. A new model for the assessment of coaches is discussed, together with implications of the proposed change for professional bodies and educators of coaches.