Eukaryotic elongation factor 2 (eEF2) is a member of the GTP-binding translation elongation factor family that is essential for protein synthesis. eEF2 kinase (eEF2K) is a structurally and functionally unique protein kinase in the calmodulin-mediated signaling pathway. eEF2K phosphorylates eEF2, thereby inhibiting eEF2 function under stressful conditions. eEF2K regulates numerous processes, such as protein synthesis, cell cycle progression, and induction of autophagy and apoptosis in cancer cells. This review will demonstrate the mechanisms underlying eEF2K activity in cancer cells under different stresses, such as nutrient deprivation, hypoxia, and DNA damage via eEF2 regulation. In vivo, in vitro, and clinical studies indicated that eEF2K may be a novel biomarker and therapeutic target for cancer.