This paper evaluates the integration of climate adaptation into the sectoral policy making of the European Commission, particularly following the publication of the European Union Adaptation Strategy. Drawing on insights from institutionalist theory it develops an analytical framework to better understand the underlying processes that may operate to either facilitate or block policy integration efforts. Empirically it focuses on climate change adaptation integration in key EU policy sectors: coasts and marine, agriculture and biodiversity, health and water. It finds that the integration of adaptation into sectoral policy-making is largely dependent on institutional dynamics at the EU-level combined with how member states and wider sectoral stakeholders engage with adaptation concerns. In particular, too many policy objectives at the EU-level of policy-making combined with member states’ ambivalence, has tended to hamper the integration of adaptation goals. In sectors which have had more recent and regular exposure to climate impacts such as agriculture these factors appear to have had less impact on integration as stakeholders may be more aware of some sectoral vulnerabilities.