MicroRNAs act as crucial post-transcriptional regulators of various biological processes. Their role in regulating the differentiation and development of the various immune cells of the body is of paramount importance. The development of immune cells from the hematopoietic progenitors involves the complex interplay of transcription factors, cell signaling proteins and growth factors. MicroRNAs govern and sometimes work in a common axis alongside these factors to regulate the differentiation of immune cells. MicroRNAs are also involved in regulating the functions of innate immune cells such as phagocytosis, antigen presentation, endotoxin tolerance and natural killer cell cytotoxicity. Several microRNAs have shown to be activated during the inflammatory response and they limit the excessive immune response. The dysregulation of several microRNAs have shown to cause uncontrolled production of inflammatory cytokines resulting in various diseases. Overall, microRNAs are found to be crucial regulators of the development and function of innate immune cells and maintenance of immune homeostasis.