This paper examines the dynamics at play in ongoing efforts to cultivate negotiation capacity among professionals working in the humanitarian sector. Based on extensive interviews conducted with humanitarian practitioners, this paper addresses three overarching issues. The first is humanitarian professionals' current understanding of humanitarian negotiation as a concept. On this issue, the paper examines the difficulties of defining humanitarian negotiation and the competing answers to the question of how to conceptually delineate humanitarian negotiation as an activity. The second is the types of negotiation capacity—cognitive, emotional, social, and cultural—that humanitarian practitioners deem to be relevant to their work. The third is the difficulties likely to be faced as capacity building efforts in this field continue to unfold. Overall, this paper aims to paint a portrait of the state of humanitarian negotiation capacity building, as well as what will be needed moving forward.