Despite migrants’ considerable contributions to the development of host and home communities, as well as the imperative to uphold the human right to health and to improve public health, many migrants are left behind and unaccounted for in health systems. The realization of UHC for migrants requires innovative, evidence-based policies and sustainable financial mechanisms that emphasize whole-of society and whole-of-government actions, and involve migrants, including health workers, as co-developers of health services. Migrants and mobile populations can face many obstacles in accessing essential health care services due to several factors including irregular immigration status, language barriers, discrimination, a lack of migrant-inclusive health policies and lack of affordable health services. Such disparities impact the well-being of migrants and host communities and undermine the realization of global health goals. The recent High Level political declaration on UHC makes specific reference to migrants and refugees, and several recent global frameworks highlight the critical importance of including migrants within UHC. Without migrant health coverage, there is no UHC. We must leave no migrant behind.