Hypoxia is a hallmark of progressive cancer. Hypoxic cancer cells trigger glycolysis in response to a decreased O2 supply to meet metabolic and bioenergetic demands. Meanwhile, these responses to hypoxia and alterations of the microenvironment promote cancer cell metastasis by increasing transcription of hypoxia-inducible factor (HIF)-regulated genes. However, the detailed mechanism by which hypoxia regulates cancer cell metastasis and glycolysis remains to be investigated. In the present study, we identified that metadherin (MTDH), a multifaceted oncogene, is involved in the regulation of head and neck squamous cell carcinoma (HNSCC) metastasis and invasion under hypoxic conditions. Furthermore, the study indicated that there is a positive feedback loop between HIF-1α and MTDH in HNSCC cells, and that hypoxia promotes HNSCC cell metastasis and epithelial-mesenchymal transition by mediating the HIF-1α-MTDH loop. These findings implicate HIF-1α-MTDH as a promising target for anticancer drugs in solid tumors, and help to explain the pro-tumorigenic and unfavorable effect of MTDH on HNSCC observed in our previous studies.