miR-429 is a member of miR-200 family. Accumulated evidence has indicated that miR-429 dysregulation is involved in the epithelial-mesenchymal transition (EMT), progression, development, invasion, metastasis, apoptosis and drug resistance of a variety of cancers. miR-429 might specifically function either as a tumor suppressor or promoter candidate for certain cancers depending on the particular types of tumor cells/tissues. miR-429 appears to have a tumor-suppression role in renal cell carcinoma (RCC), breast cancer (BC), gastric carcinoma (GC), glioblastoma (GBM), esophageal cancer (EC), osteosarcoma, oral squamous cell carcinoma (OSCC), cervical cancer (CC), pancreatic cancer, tongue squamous cell carcinoma (TSCC), nephroblastoma, nasopharyngeal carcinoma (NPC) and soft tissue sarcomas. On the other hand, miR-429 has a tumor-promotion role in endometrial cancer (EmCa), prostate cancer (CaP) and lung cancer (LC). However, miR-429 shows paradoxical role in colorectal cancer (CRC), hepatocellular carcinoma (HCC), bladder cancer and ovarian cancer (OC). This article summarizes the associations between miR-429 and malignant tumors as well as potential action mechanisms. miR-429 has a potential to be used in the future as a biomarker for the diagnosis, treatment and prognosis of certain cancers.