miRNAs (microRNAs) are a class of endogenous, small non-coding RNAs, typically approximately 17–25 nt in length. By specifically binding to target mRNAs, miRNAs can induce target mRNA degradation or repress translation, thereby participating in post-transcriptional gene regulation. miRNAs are involved in a wide range of biological processes, including embryonic development, antiviral defense, hematopoiesis, organogenesis, cell proliferation and apoptosis, lipid metabolism, and tumor growth. They play important roles in diverse physiological and pathological processes and have been extensively investigated as potential disease biomarkers. In addition, researchers are exploring ways to modulate miRNA function and develop novel mechanisms of action, including the regulation of gene expression, with the aim of harnessing miRNAs as potential therapeutic strategies for disease intervention and treatment.