The microRNA known as miR-128-3p demonstrates widespread tissue-specific expression with its genetic locus situated on human chromosome 2 (2q21.3), and is a multifunctional regulator with tissue-specific expression patterns that critically influences cellular homeostasis and disease pathogenesis. By engaging with the 3′ untranslated region (3′ UTR) of target mRNA molecules, miR-128-3p exquisitely modulates gene expression levels, thereby orchestrating cellular proliferation, immune responses, metabolic equilibrium, and tumorigenesis. Studies on miR-128-3p in different cancers have revealed diverse expression patterns and functional roles. Intriguingly, due to its ability to target multiple genes and signaling pathways, as well as being regulated by various genes themselves, miR-128-3p exhibits both tumor-suppressive and oncogenic effects under neoplastic conditions. This review summarizes the expression patterns and complex regulatory mechanisms of miR-128-3p across various cancers. A profound understanding of the significance and regulation of miR-128-3p in cancer will drive the development of innovative therapeutic strategies using this molecule for combating human cancer and immune-related disorders.