Our present study confirmed radiation can promote the in vitro migration and invasion of triple negative breast cancer (TNBC) cells and increase the expression of epithelial–mesenchymal transition (EMT) related transcription factor ZEB1, while had no effect on Snail, Slug or Twist. Knockdown of ZEB1 attenuated radiation induced cell migration and invasion, suggesting that ZEB1 is essential for radiation induced progression of TNBC. Radiation increased the protein stability of ZEB1, while had no effect on its mRNA expression. Particularly, the upregulation of ATM, which can phosphorylate and stabilize ZEB1, was involved in radiation induced upregulation of ZEB1. Collectively, we found that radiation can promote the migration, invasion and EMT of TNBC cells through stabilization of ZEB1 via ATM signals.