This thesis written by Mr. Moritz Hauer specifically directs focus towards addressing key environmental concerns during humanitarian assistance. Adressing the environmental aspects of humanitarian projects and interventions is critical to prevent additional hazards, reduce risks, and to not further increase the vulnerability of disaster-affected populations. However, the environment remains an underappreciated cross-cutting issue within the humanitarian sector and efforts to systematically integrate environmental concerns into humanitarian assistance as well as to reduce its environmental impacts are quite limited. This paper analyzes the current state of environmental mainstreaming in humanitarian assistance and seeks to identify the main barriers hindering the systematic integration of environmental concerns.