Two-dimensional transition-metal dichalcogenides (TMDCs) with intrinsically broken crystal inversion symmetry and large second-order nonlinear responses have shown great promise for future nonlinear light sources.However,the sub-nanometer monolayer thickness of such materials limits the length of their nonlinear interaction with light.Here,we experimentally demonstrate the enhancement of the second-harmonic generation from monolayer MoSe2 by its integration onto a 220-nm-thick silicon waveguide.Such on-chip integration allows for a marked increase in the interaction length between the MoSe2 and the waveguide mode,further enabling phase matching of the nonlinear process.The demonstrated TMDC-silicon photonic hybrid integration opens the door to second-order nonlinear effects within the silicon photonic platform,including efficient frequency conversion,parametric amplification and the generation of entangled photon pairs.