A solution-processable organosiloxane-based organic–inorganic hybrid gate dielectric layerfor application in organic thin-film transistors has been synthesized by a sol–gel process. Inthe sol–gel derived hybrid film, owing to an incomplete condensation reaction, silanolgroups serve as functional groups of the inorganic siloxane backbone. In order to investigatethe influence of the silanol groups on the electrical performance of transistors withorganosiloxane-based dielectrics, transistors employing hybrid dielectrics with differentamounts of the silanol group were prepared and electrical performance parameters such asoff-current, threshold voltage, field-effect mobility, and hysteresis were analysed.