Member states of the World Health Organization (WHO) African (AFR) and Eastern Mediterranean (EMR) regions have set goals for measles elimination by 2020 and 2015, respectively. The two WHO regions include AFR member states Ethiopia and Kenya, and EMR member state Somalia. All three countries are in the Horn of Africa, where measles remains endemic, with periodic outbreaks despite efforts to achieve elimination goals. This report describes outbreaks that occurred in the Horn of Africa during 2010-2011. The outbreaks were exacerbated by a complex humanitarian emergency in Somalia, with an influx of an estimated 600,000 refugees into camps in Kenya and Ethiopia near the borders with Somalia. During 2010-2011, a total of 9,756 measles cases were reported in Ethiopia and 2,566 in Kenya, with wide age distributions, and 16,135 were reported in Somalia, with 78% occurring among children aged <5 years. Cases occurred predominantly in unvaccinated persons. Outbreak response immunization (ORI) strategies were implemented; however, outbreaks continued. To reach AFR and EMR measles elimination targets, uniform high coverage with 2 doses of measles-containing vaccine (MCV) must be achieved and maintained in Horn of Africa countries, including in refugee camps.