Virtually every mammalian cell contains the cytoplasmic protein kinase General Control Non-depressible 2 (GCN2), which allows cells to cope with stresses such as nutrient shortage. While GCN2 is not essential for normal cells, in many can-cers GCN2 assumes a pivotal role, becoming indispensable for cell growth and sur-vival. This has spurred significant interest in GCN2 as a promising target for anti-cancer therapies. In this review, we give an overview of the known links between GCN2 and cancer.