Chemotherapy is widely used for the treatment of glioma. Given the high resistance of brain neoplasm tissues to chemotherapy, it is important to find new methods to improve the effects of chemotherapy. However, the molecular mechanisms underlying glioma resistance to chemotherapy are largely unknown. Here, we demonstrate that CDK6, a cell cycle regulator, is significantly upregulated in glioma cells, and the increasing expression of CDK6 correlates well with the grades of glioma malignancy. Using shRNA-mediated CDK6 knockdown, we found that the proliferation and survival of tumor cells were dramatically inhibited. Moreover, CDK6 knockdown in the U251 glioma cell line caused significant increase in the apoptosis of U251 cells treated with temozolomide (TMZ). Furthermore, CDK6 knockdown reduced the expression level of drug resistance genes such as MRP and MDR. These data indicate that CDK6 is an important mediator of glioma resistance to chemotherapy. Our findings provide a new strategy for the development of chemotherapy sensitizer.