Metastasis is the primary cause of mortality in lung cancer patients, with the epithelial-mesenchymal transition (EMT) process conferring increased metastatic potential to carcinoma cells. While emerging evidence suggests that TNS1 contributes to carcinoma metastasis, it remains unclear the role of TNS1 in EMT. In this study, we reveal TNS1 as an indispensable factor in TGF-β and hypoxia mediated EMT process. Elevated TNS1 protein levels are closely correlated with a worse prognosis in lung cancer patients. TNS1 is also found to potently promote EMT process and tumor metastasis in vitro and in vivo. Mechanistically, TNS1 expression is mediated by the transcription factor SMAD3 in TGF-β signaling. Moreover, TNS1 interacts with and modulates ZEB1 expression, preventing ZEB1 ubiquitination degradation. Therefore, our study reveals the role of TNS1 in the EMT process and suggests that TNS1 promises to a candidate for targeted cancer therapy.