With displacement occurring at record levels and often on a protracted basis, there is increasing interest in the potential to link humanitarian displacement responses with social protection systems. This article discusses how social protection and humanitarian systems can work together to meet the needs of displacement-affected populations, based on the findings of a three-year research project that drew on global literature alongside mixed-methods data collected in 2021 in Cameroon, Colombia, and Greece. The article discusses five lessons: (1) displaced populations’ distinct needs and implications for social protection design and delivery; (2) inadequate social protection for host communities and implications for social cohesion; (3) the priority basis for evaluating linkage approaches; (4) the need for sustained international financing; and (5) the general importance of greater transparency and collaboration. It concludes with recommendations for further research to build the nascent evidence base on this topic.