Over the last twenty years, there has been a growing interest in measuring sexual wellbeing, including by a WHO/UNFPA working group in 2007, which sought clarity on key dimensions and asked for indicators of these to be devised. However, there remains a lack of conceptual clarity surrounding the concept of sexual wellbeing, which may create variation in what is being assessed and to what we are referring. This paper proposes one way in which to achieve conceptual clarity might be through the utilisation of a Capability Approach, thereby posing a new set of normative questions about what sexual wellbeing is. The central argument in this paper is for researchers, theorists and practitioners to focus more fully on a person's freedom to achieve sexual wellbeing within a particular social and cultural context. We suggest the kinds of data that might need to be captured to operationalise and measure such an understanding. By offering new critical insights, we hope to drive forward empirical and methodological development in the evaluation of sexual wellbeing.