Wearable potentiometric sensors have attracted significant attention in advancement in personal healthcare devices and diagnostics due to their remote, non-invasive, and continuous monitoring of health-related signals during daily activities. All-solid- state ion-selective electrodes have promoted practical applications, offering ease of operation, rapid measurement, and low energy consumption. Here, this review describes the principles, structure, and characterization of a potentiometric sensor based on the guidelines of the International Union of Pure and Applied Chemistry (IUPAC). Wearable sensor applications to detect various electrolytes in sweat samples were also discussed, along with their challenges and future opportunities to improve the reliability and accuracy of sensor readings.