Background: As a way of tackling child mortality, many countries in the world depend on their respective health-care system. But governments of most countries in Africa are yet to provide robust funding of their health-care systems as many people still depend on the out-of-pocket payment to receive health services. Against this backdrop, this study used annual panel data to assess the effect of health-care expenditure and immunisation on the under-five mortality rate in 30 selected African countries for the period 2000-2017. Methods: Multiple regression technique was adopted for the data analysis and the robust fixed regression estimator was preferred to the random effects as determined by Hausman test.Results: The findings indicated that domestic government general health expenditure had a significant negative effect on the under-five mortality rate. However, the effect of domestic private health expenditure on under-five mortality was not significant while external health expenditure had a significant negative effect on under-five mortality rate. The impact of diphtheria immunisation on under-five mortality was significant. Conclusions: Except domestic private health expenditure, government and external forms of health expenditure coupled with diphtheria immunisation were significant factors for the reduction of the under-five mortality in the selected countries.