Stressors substantially affect the physiology of cells. Depending on the severity and duration of stress exposure, cells either strive to maintain homeostasis or adapt by adjusting their gene expression patterns. One of the mechanisms to change gene expression is regulating the microRNA (miRNA) levels and activities of microRNA-protein complexes. A fine tuning of the interaction of miRNAs with their mRNA targets determines the specificity of protein synthesis and the quantitative composition of the protein pool in stress. The review considers the mechanisms that regulate miRNA biogenesis, miRNA-mediated mRNA repression, and activity of miRNA-protein complexes in animal cells exposed to various stress factors.