AbstractHumidity control plays an important role across various industries, including pharmaceuticals, semiconductors, aerospace, food processing, and agriculture. Regulations have been established for optimal humidity levels and humidity sensing requirements to ensure human comfort, product quality, and energy efficiency. This paper examines the regulations across humidity-controlled industries, studies the water–surface interactions of reactive materials, and reviews the key parameters of humidity sensors from the perspective of sensitivity, accuracy, repeatability, and stability. In addition, the paper investigates the advancement in sensing technologies with the development of hygroscopic nanomaterials. The adsorption, absorption, and desorption of water molecules of respective surface morphology in humidity sensing improvement have been discussed. This paper also aims to provide an overview of the strategies towards high-precision humidity sensors in moisture-sensitive applications with enhanced performance, reliability, and sustainability.