This paper explores the factors the literature suggests help organizations collaborate during disaster response. The nature of disasters requires that people and organizations collaborate; yet, collaboration has been frequently identified as a problem by policymakers and researchers alike. It would be of value to policymakers and researchers if there was an understanding of the factors that contribute to collaboration. The paper attempted to address this issue. It identifies four categories of variables that the literature suggests lead to inter-organizational collaboration including leadership, relationships, culture, and inter-dependency. The paper also suggests how understanding of these factors might be applied in practice, policy, and future research.