Vulnerable ecological areas are often seriously impacted by armed conflicts. In theory, these areas could benefit from the safeguards offered by the international humanitarian law (IHL) regimes of “demilitarized zones” and “undefended localities”, but in practice, these regimes – which are designed to protect human beings from the violence of hostilities, and whose application entirely depends on the goodwill of belligerents – are rarely triggered to protect the environment as such. However, international environmental law (IEL) contains a rich and diversified normative framework which organizes the establishment and management of areas of major ecological importance. While this framework has not primarily been conceived to apply to war-related situations, it could nonetheless play a substantive role in strengthening the IHL normative regimes in two respects. Firstly, it could provide interpretative guidance for these regimes so that they can be oriented towards more “ecocentric” purposes and can be read in accordance with the most advanced IEL standards and mechanisms governing biodiversity hotspots (the “environmentalization” of IHL). Secondly, IEL norms and practices could directly apply during warfare and thus complement IHL in many respects. That said, the co-application of IEL and IHL raises difficult issues of compatibility between these regimes, requiring inter alia that the IEL framework governing protected areas be adapted to the needs and specificities of armed conflicts (the “humanitarization” of IEL).