The article reviews the critical role of potassium (K) in plant stress response, focusing on its effects against biotic and abiotic stresses. Potassium is essential for various biochemical and physiological processes in plants, including enzyme activation, protein synthesis, photosynthesis, osmoregulation, and stress resistance. The review discusses how K availability influences plant growth, anatomy, morphology, and metabolism, and explores the physiological and molecular mechanisms of K's function in stress resistance. It highlights the potential for improving plant stress resistance by modifying K fertilizer inputs and selecting appropriate plant species or varieties. The article also emphasizes the importance of maintaining an optimal K nutritional status to enhance plant resistance to biotic and abiotic stresses, such as diseases, pests, drought, salinity, cold, and waterlogging. The review concludes with suggestions for future research to further understand the role of K in plant stress response.The article reviews the critical role of potassium (K) in plant stress response, focusing on its effects against biotic and abiotic stresses. Potassium is essential for various biochemical and physiological processes in plants, including enzyme activation, protein synthesis, photosynthesis, osmoregulation, and stress resistance. The review discusses how K availability influences plant growth, anatomy, morphology, and metabolism, and explores the physiological and molecular mechanisms of K's function in stress resistance. It highlights the potential for improving plant stress resistance by modifying K fertilizer inputs and selecting appropriate plant species or varieties. The article also emphasizes the importance of maintaining an optimal K nutritional status to enhance plant resistance to biotic and abiotic stresses, such as diseases, pests, drought, salinity, cold, and waterlogging. The review concludes with suggestions for future research to further understand the role of K in plant stress response.