Abstract: MicroRNA-506 (miRNA- 506 ) is located in the X chromosome and influences various processes, such as cell proliferation, apoptosis, senescence, cell cycle, cell differentiation, epithelial- to- mesenchymal transition, angiogenesis, invasion, and metastasis, through post-transcriptional regulation of its targets. Recent studies have shown that miRNA- 506 plays an important role in tumorigen -esis and progression of many types of tumors. In vitro and in vivo experiments revealed that miRNA-506 suppresses progression of sev-eral tumors and promotes response of tumor cells to chemotherapy. However, miRNA-506 plays different roles in different tumors. This review summarizes the functions and mechanisms of miRNA- 506 in different tumors to identify a new target for the targeted ther-apy of certain tumors.