Laser reduced graphene oxide-based interdigitated microelectrodes were functionalized with TiO2 nanoparticles towards sensor applications. Two kinds of interdigitated microelectrodes were prepared by laser direct writing using graphene oxide (GO) and TiO2 nanoparticles. One is a TiO2 nanoparticle-deposited interdigitated microelectrode consisting of GO and laser-induced reduced graphene oxide (rGO), where the rGO/GO/rGO structure was prepared by laser direct writing on a GO-coated PET film and then a TiO2 sol solution was drop-casted on the electrode. Another is a TiO2/rGO hybrid interdigitated microelectrode prepared by laser direct writing on a TiO2 nanoparticle-GO hybrid film. The UV light sensitivity of the TiO2 nanoparticle-deposited rGO/GO/rGO interdigitated microelectrode and the oxygen quenching behavior were applied to oxygen sensing. The output voltage from the TiO2 nanoparticle-deposited rGO/GO/rGO structure in the AC detection mode under 369 nm LED irradiation showed clear relationship with the degree of vacuum. The sensing behavior was based on the photo-generated carrier quenching by oxygen. The irradiation of a 405 nm blue violet laser to a TiO2 nanoparticle-GO hybrid film caused the crystal phase transition from anatase to rutile TiO2 accompanying the melting of anatase nanoparticles. The TiO2/rGO hybrid interdigitated microelectrode consisting of anatase TiO2, rutile TiO2, and rGO was prepared by laser direct writing. The TiO2/rGO hybrid interdigitated microelectrode showed the response to visible light irradiation.