The use of sol-gel chemistry has afforded the development of a diverse range of chemical sensors, due to the ease with which the process can be modified to tailor properties of the material such as porosity and hydrophobicity. Furthermore, sol-gel films can be deposited on a variety of substrates, thus allowing flexibility in sensor configuration. This chapter will provide an overview of the latest developments in sol-gel-based sensors. Applications reviewed include sensors for determination of gases, humidity, pH, ionic species, forensic analysis and biosensing.