Ecopolitics entered political discourse firstly as an alternative debate to mainstream politics and ideological refutation of the established political order, and that way gained public expression in social movements of contestation. Subsequently, it emerged intertwined in the discourse of party politics and finally came to reach the core of contemporary political systems and their political agendas. The construction and the spreading of the ecopolitical discourse are addressed in the first part of the article. The way it entered the field of public policies is the core concern of the second part, with a focus on international and global security policies. Ecopolitical thinking has contributed to a shift in international security paradigms, from the conventional, realist and state-centred national security paradigm to approaches that privilege human security and global sustainability. To the end, the article reviews extant policy areas connecting environment with security.