BACKGROUND Better maternal education has been credited with making a major contribution to infant mortality decline. Most of the evidence is based on cross-sectional analyses, which show a strong correlation between maternal education and infant mortality. However, crosssectional analyses do not provide an estimate of the contribution of maternal education to infant mortality decline. OBJECTIVE The major objective is to obtain a more accurate estimate of the contribution of maternal education to infant mortality decline. METHODS Pooling data from all available phases of the Demographic and Health Survey, this article presents a longitudinal, individual-level analysis of the determinants of trends in infant mortality in Indonesia. RESULTS Better maternal education explains 15% of the infant mortality decline in Indonesia from 1980 to 2015.