Potassium channels regulate excitability, epithelial ion transport, proliferation, and apoptosis. In pancreatic ducts, K channels hyperpolarize the membrane potential and provide the driving force for anion secretion. This review focuses on the molecular candidates of functional K channels in pancreatic duct cells, including KCNN4 (K 3.1), KCNMA1 (K1.1), KCNQ1 (K7.1), KCNH2 (K11.1), KCNH5 (K10.2), KCNT1 (K4.1), KCNT2 (K4.2), and KCNK5 (K5.1). We will give an overview of K channels with respect to their electrophysiological and pharmacological characteristics and regulation, which we know from other cell types, preferably in epithelia, and, where known, their identification and functions in pancreatic ducts and in adenocarcinoma cells. We conclude by pointing out some outstanding questions and future directions in pancreatic K channel research with respect to the physiology of secretion and pancreatic pathologies, including pancreatitis, cystic fibrosis, and cancer, in which the dysregulation or altered expression of K channels may be of importance.