This study uses annual time series data on under five mortality rate (U5MR) for Gabon from 1960 to 2020 to predict future trends of U5MR over the period 2021 to 2030. Residuals and forecast evaluation criteria indicate that the applied model is stable in forecasting U5MR. This study utilizes Holt’s linear exponential smoothing model to forecast future trends of U5MR in Gabon. The optimal values of smoothing constants α and β are 0.9 and 0.1 respectively based on minimum MSE. The results of the study indicate that annual U5MR will decline over the out of sample period. Therefore, we implore the government of Gabon to channel more resources to maternal and child health (MNCH) program activities to ensure availability of adequate medical supplies and staff at all levels of healthcare. In addition, there is need to aggressively implement health related SDGs that will positively impact on population health such as poverty reduction, infrastructure development, and sustainable production and consumption.