The development and characterization of resistive humidity sensors based on Chitosan on a glass substrate is reported. The sensor electrodes are made of laser-induced graphene derived from Chitosan, which represents a sustainability advancement by eliminating the need for adding additional materials during fabrication. Depending on the sensor design, a high sensitivity can be achieved either in the lower or higher humidity range with a total operation span from 40 to 100% rH. Both sensors exhibit good stability, especially at high humidity levels (80% rH) over a 24-h cycle. The Chitosan-based sensors, hence, offer an excellent combination of sustainability and high performance, making them an attractive solution for countless humidity sensing applications.