As part of the European Union’s (EU) renewable energy and climate targets and its drive for sustainability, energy efficiency, and environmental protection, various elements of the defense sector in Europe are undertaking their own green initiatives. This is particularly important as the defense sector is one of the biggest public consumers of energy in the EU. This article asks to what extent, how, and why elements of the defense sector in Europe have engaged in greening. By examining four categories in a relevant typology of greening—ceremonial greening, holistic greening, regulatory greening, and competitive greening—this article argues that the defense sector in Europe is far from being a holistic green actor. Rather, Europe’s militaries, defense institutions, and defense firms exhibit a strong sense of self-interest in greening—embodied in defense market competition and regulation—and tend toward delegating green innovation to the market within an increasingly regulated context.