Implementation of national adaptation policy is advancing. There also appears to be a shift, albeit slow, from monitoring of implementation to evaluation of outcomes of the policy. However, there is an absence of an agreed definition or metrics to indicate when national level implementation fails or goes wrong. The concept of maladaptation remains elusively defined in the adaptation policy sphere but is often evoked in national adaptation plans. Empirical research on maladaptation related to national adaptation policies is lacking, despite claims of it increasingly taking place. This review discusses whether maladaptation should be operationalised as a concept in national adaptation policy, how it would be done and what could it take to make it happen. The paper argues that unless failure of adaptation policy is considered, understanding the adaptation gap, for example, becomes even more challenging.