In this study, a remote doping (RD) method is proposed in which SiO x is used as the remote doping agent without directly contacting transition metal dichalcogenide (TMD) materials. It is found that a doping density as high as 1.4 × 10 13 cm −2 without reducing the mobility of the doped materials can be achieved and even after 1 month later the doping concentration remained as high as 1.2 × 10 13 cm −2 . We observe that SiO x is able to dope several popular 2D transition metal dichalcogenides, including MoS 2 , WS 2 , and WSe 2 . Notably, it possesses a lower k value than that of stoichiometric silicon dioxide oxide, which is very attractive for spacer doping in terms of the perspective of circuit operation. In our experiments, MoS 2 and WS 2 underlap top-gate devices exhibited 10× and 200× increases in their on-currents, respectively, after being doped with SiO x . These results indicate that SiO x doping can be implemented to manufacture high-performance 2D devices.