Introduction: Gene expression regulation is essential for correct functioning of the cell. Complex processes such as development, apoptosis, cell differentiation, and cell cycling require a fine tuning of gene expression. microRNAs (miRNAs) are small RNAs that have been recognized as key components of the gene expression regulatory machinery. microRNAs are a class of small RNA regulators that are involved in numerous cellular processes, including development, proliferation, differentiation, neurogenesis, and plasticity. miRNAs are critical contributors to the regulation of gene expression in the nervous system. Conclusion: Emerging evidence indicates that microRNAs regulate both the development and function of the nervous system. Deficiency in microRNA function has also been implicated in a number of neurological disorders. Understanding the roles of microRNAs will provide new insights into the complexity and operation of the nervous system.