This study aims to understand and explore the concepts of Environmental Security and Environmental Peacebuilding, in view of identifying opportunities for engagement and integration between Security Sector Reform and Environmental Peacebuilding. We argue that Security Sector Reform, in contexts of fragility and conflict, faces the systemic-dependent interaction of impacts from the factors of the climate change-conflict nexus, so it must develop its model of action in alignment with the trends of adaptation and evolution of the way of acting of Environmental Peacebuilding. Aware that Environmental Security faces what is already considered an existential global threat with the duty to protect and care for humans and non-humans and having verified that the evolution trends of Environmental Peacebuilding and Security Sector Reform are similar and susceptible to alignment, we conclude that it is appropriate their engagement and integration, in that contexts, and this should be worked on and developed by researchers and practitioners in the future.