Objectives Maternal folic acid supplementation is considered mandatory in almost every country in the world to prevent congenital malformations. However, little is known about the association of maternal folic acid intake with the occurrence of childhood cancer. Hence, this study aimed to determine the effects of maternal folic acid consumption on the risk of childhood cancer. Methods A total of 158 related articles were obtained from PubMed, Google Scholar, Scopus, and ProQuest using standardized keywords, of which 17 were included in the final review. Results Eleven of the 17 articles showed a significant protective association between maternal folic acid supplementation and childhood cancer. Using a random-effects model, pooled odds ratios (ORs) showed a protective association between maternal folic acid supplementation and childhood acute lymphoblastic leukaemia (OR, 0.75; 95% confidence interval [CI], 0.66 to 0.86). However, there was no significant association between maternal folic acid supplementation and acute myeloid leukaemia (OR, 0.70; 95% CI, 0.46 to 1.06) or childhood brain tumours (OR, 1.02; 95% CI, 0.88 to 1.19). Conclusions Maternal folic acid supplementation was found to have a protective effect against childhood acute lymphoblastic leukaemia. Thus, healthcare professionals are recommended to provide regular health education and health promotion to the community on the benefits of folic acid supplementation during pregnancy.