The pogo transposable element derived zinc finger protein, POGZ, is notably associated with autism-like or intellectual disabilities through its role in gene transcription. Indeed, many proteins involved in neurological development are often dysregulated in cancer. We provide the first experimental evidence that POGZ influences the growth and metastatic spread of triple negative breast cancers (TNBC). Utilizing a well-characterized immunocompetent model of TNBC, we show that POGZ exerts a dual role, both as a tumor promoter and metastasis suppressor. Mechanistically, we show that POGZ loss potentiates TGFβ pathway activation in TNBC, to exert cytostatic effects while simultaneously increasing the mesenchymal and migratory properties of breast tumors. Finally, we demonstrate that whereas POGZ levels are elevated in human breast cancers, the most aggressive TNBC tumors, including those with increased mesenchymal and metastatic properties, dampen POGZ levels, associated with inferior clinical outcomes. Combined these data suggest that POGZ is a critical regulator of the early stages of metastatic cascade Overall design: POGZ was genetically ablated in murine 4T1 TNBC. Cells lines (3 KO replicates, 3 VC replicates) and syngeneic BalbC derived tumors (3 KO replicates, 3 VC replicates) were subjected to RNAsequencing.