Sirtuin6 (SIRT6) has been shown to suppress glycolysis and enhance DNA repair. As a tumor suppressor, SIRT6 can directly deacetylate hypoxia-inducible factors (HIFs). In this study, we examined the role of SIRT6 and HIFs in the progression of RCC (renal cell carcinoma). An MTT assay and Hoechst staining were performed to determine the viability and apoptosis of RCC cells, respectively. RT-qPCR and western blotting were used to determine the levels of SIRT6 and HIF1 alpha proteins. SIRT6 was overexpressed using an adenovirus vector and was inhibited using a specific siRNA. SIRT6 protein levels were reduced, whereas the expression of HIF1 alpha was increased in renal cell carcinoma (RCC) tissues and cell lines. The MTT assay showed that overexpression of SIRT6 could decrease 786-O cell viability. Moreover, SIRT6 overexpression decreased RCC cell colony formation and increased RCC cell apoptosis. Western blot analysis revealed that SIRT6 reduced HIF1 alpha expression and downstream signaling in RCC cells. A ChIP assay demonstrated that SIRT6 overexpression significantly reduced H3K9 and H3K56 acetylation in the promoter regions of glycolytic genes. More importantly, HIF1 alpha inhibition partially rescued the phenotype of SIRT6-silenced RCC cells. Taken together, these results demonstrated for the first time that SIRT6 inhibited RCC progression through the inhibition of HIF1 alpha expression in vitro.