This work deals with the study of hydrothermally synthesized zinc oxide (ZnO) loaded mesoporous SBA-15 hybrid nanocomposite for relative humidity sensing (RH) at room temperature. The sensor exhibits an excellent similar to 5 orders impedance change along with excellent linearity, quick response time (17 s), rapid recovery time (18 s), negligible hysteresis (1.2%), good repeatability, and stability (1.8%) in 11%-98% RH range. In addition, complex impedance spectra of the sensor at different RHs were analyzed to understand the humidity sensing mechanism. Our study can open a new way for realizing ZnO/SBA15 hybrid nanocomposite for fabrication of high-performance RH sensors.