MicroRNA (miRNA) dysregulation is well-documented in psychiatric disease, but miRNA dynamics during adolescent and early adult brain maturation, when symptoms first appear for many of these diseases, remain poorly understood. Here, we use RNA sequencing to examine miRNAs and their mRNA targets in cortex and hippocampus from early, mid-, and late adolescent and adult mice. We also use Quantitative Proteomics by tandem mass tag mass spectrometry (TMT-MS) to examine protein dynamics in cortex from the same subjects.