Organic field-effect transistors have gained much attention for their potential use in low-cost, large-area, flexible electronics. High-performance organic transistors require a low density of grain boundaries in their organic films and a reduction of charge traps at the semiconductor-dielectric interface for efficient charge transport. In this respect, the role of the dielectric material is crucial because it primarily determines the growth of the film and the interfacial trap density. Here, we demonstrate the use of chemical-vapor-deposited hexagonal boron nitride (CVD h-BN) as a scalable growth template/dielectric for high-performance organic field-effect transistors. The field-effect transistors based on C60 films grown on single-layer CVD h-BN exhibit an average mobility of 1.7 cm^2V^-1s^-1 and a maximum mobility of 2.9 cm^2V^-1s^-1 with on/off ratios of 10^7. The structural and morphology analysis shows that the epitaxial, two-dimensional growth of C60 on CVD h-BN is mainly responsible for the superior charge transport behavior. We believe that CVD h-BN can serve as a growth template for various organic semiconductors, enabling large-area, high-performance flexible electronics.