The Activating Transcription Factor (ATF2) gene encodes a transcription factor important for normal cellular development and survival. In addition to its role as a transcription factor, ATF2 functions in the DNA damage response and in control of HAT complex activity. So far genetic changes in ATF2 have not been identified in human tumors. Yet altered expression and subcellular localization of ATF2 are associated with tumor stage and prognosis. Our studies in melanoma tumor models identified oncogenic ATF2 activity correlating with development of this tumor type. Inhibiting ATF2 suffices to impede melanoma development. Yet work in other tumor models, including breast and skin tumors reveals that ATF2, in cooperation with mutated oncogenes or tumor suppressor genes, can also elicit tumor suppressor function. These findings suggest tissue- and tumor-specific function of ATF2. This review summarizes the current understanding of ATF2 regulation and function.