Twin children are more likely to die than singletons. This is an additional burden in sub-Saharan African (SSA) countries, as child mortality levels are already higher than anywhere else. This article provides estimates of under-5 mortality rates (U5MRs) for twins and singletons in SSA from 1986 to 2016. It describes the geographical variations and changes over time. It also describes the variation of twins’ excess mortality according to age from 0 to 5 years. Additionally, it analyzes the factors associated with twins’ excess mortality. We used data from 156 national surveys from 42 countries. We estimated U5MRs for twins and single children and built a Cox model to analyze factors associated with excess mortality among twins. Although child mortality has declined on the continent, twins’ excess mortality remains very high. U5MRs are, on average, 3 times higher among twins than singletons. The Cox model shows that all other things being equal, the adjusted hazard ratio of under-5 mortality (U5M) is 3.2 (2.9−3.3; p < .001) times higher among twins than singletons. The main factors associated with excess mortality risks among twins are biomedical and nutritional features, such as low birth weight, non-use of cesarean section delivery, and lack of breastfeeding. Health policy makers in SSA should be aware of the vulnerability of twins, and interventions to prevent their early deaths should be considered.