Hypertension is a global burden and a major contributor to cardiovascular disease and premature death. Public health guidelines for the management of high BP contain numerous dietary recommendations, of which one is a reduction in salt (NaCl) intake. In addition, the modern diet is also characterized by low potassium (K+) content and recent guidelines propose increasing K+ intake as an alternative or complementary measure to reducing salt intake for lowering of BP. Most beneficial effects of K+ supplementation on BP involve a homeostatic response of the kidney to dietary-induced changes in extracellular K+ concentrations, particularly decreased reabsorption of NaCl in the distal convoluted tubule. However, the effects of greater K+ intake on BP are not linear, and the ideal K+ supplementation or intake for management of BP remains unclear. This article covers the mechanisms in the kidney by which changes in K+ translate to alterations in BP, the effects of altered K+ intake in animal models and human populations, and the importance of concurrent salt intake and what constitutes K+ supplementation.