Climate change adaptation has emerged as an important topic of both scientific and political interest. Adaptation science now claims a legitimate space in policy agendas based on its prospective insights in providing guidance to adaptation policy and practice. The growth in adaptation science has contributed to the development of principles and assumptions about the nature of climate adaptation, which now influence our research, policy and practice. These emergent guidelines consist of a collection of core assumptions, which have enabled the translation of the more normative and speculative aspects of adaptation into policy relevant knowledge, frequently referred to as ‘adaptation theory’. However, this more applied side of adaptation science still faces substantial difficulties in its ability to move meaningfully between theory and practice. Hence, increasing calls for closer integration of adaptation theory and practice continue to be made in order to validate how ‘adaptation theory’ can support policy and practice. Although academia has responded to these calls by focusing more research on the fundamental characteristics of ‘good’ and ‘successful’ adaptation, it is still unclear what constitutes ’adaptation theory’ and the extent it is relevant for policy- and decision-making processes.