Natural killer (NK) cells represent a fundamental aspect of the innate immunity. These cells considered as a vital part of tumor immunosurveillance by directly eliminating cancer cells and releasing cytokines. Their role is closely controlled through the equilibrium between activating and inhibitory signals. MicroRNAs (miRNA), being short non-coding RNAs, involve in controlling the differentiation, maturation, and effector responses of NK cells. Here, we highlight the functions of miRNAs in controlling NK cell lineage commitment, subset differentiation, cytotoxicity, and immune checkpoint expression. Additionally, it explores how tumor-derived factors, such as hypoxia, modulate miRNA expression, thereby impairing NK cell activity within the tumor microenvironment (TME). Additionally, we summarized how manipulating miRNA pathways could improve NK cell-based immunotherapies.