Developmental changes in the liver can significantly impact drug disposition. Due to the emergence of microRNAs (miRNAs) as important regulators of drug disposition gene expression, we studied age‐dependent changes in miRNA expression. Expression of 533 miRNAs was measured in 90 human liver tissues (fetal, pediatric 1–17 years, and adult 28–80 years; n = 30 each). In all, 114 miRNAs were upregulated and 72 were downregulated from fetal to pediatric, and 2 and 3, respectively, from pediatric to adult. Among the developmentally changing miRNAs, 99 miRNA‐mRNA interactions were predicted or experimentally validated (e.g., hsa‐miR‐125b‐5p‐CYP1A1; hsa‐miR‐34a‐5p‐HNF4A). In human liver samples (n = 10 each), analyzed by RNA‐sequencing, significant negative correlations were observed between the expression of >1,000 miRNAs and mRNAs of drug disposition and regulatory genes. Our data suggest a mechanism for the marked changes in hepatic gene expression between the fetal and pediatric developmental periods, and support a role for these age‐dependent miRNAs in regulating drug disposition.