Sweat, as a biofluid with the potential for noninvasive collection, provides profound insights into human health conditions, because it contains various chemicals and information to be utilized for the monitoring of well-being, stress levels, exercise, and nutrition. Recently, wearable sweat sensors have been developed as a promising substitute to conventional laboratory sweat detection methods. Such sensors are promising to realize low-cost, real-time, in situ sweat measurements, and provide great opportunities for health status evaluation analysis based on personalized big data. This review first presents an overview of wearable sweat sensors from the perspective of basic components, including materials and structures for specific sensing applications and modalities. Current strategies and specific methods of the fabrication of wearable power management are also summarized. Finally, current challenges and future directions of wearable sweat sensors are discussed.