This study aimed to explore the associations between maternal folic acid (FA) supplementation during different trimesters of pregnancy and newborn telomere length (TL). Data were collected from a birth cohort study of 746 mother-newborn pairs conducted from November 2013 to March 2015 in Wuhan, China. After adjustment for potential confounders, maternal FA supplementation after the first trimester and throughout pregnancy were associated with longer newborn TL [β = 0.29, 95 % confidence interval (CI): 0.20, 0.38 and β = 0.24, 95 % CI: 0.16, 0.32, respectively]. No significant association was found between maternal FA supplementation in the first trimester and newborn TL. In conclusion, a possible association between maternal FA supplementation during pregnancy with longer newborn TL was suggested in the present study. This study provides insight into the benefit of newborn TL by maternal FA supplementation during pregnancy.