The rhodium-catalyzed asymmetric synthesis of dibenzooxasilines developed by Hayashi and co-workers provides an efficient method to construct tetraorganosilicon stereocenters. In the present study, density functional theory (DFT) calculations were performed to investigate the mechanism and enantioselectivity of this reaction. Theoretical calculations indicate that the mechanism involves the initial formation of an aryloxorhodium complex followed by Rh–Si exchange to afford an arylrhodium complex. The favorable oxidative addition/reductive elimination to cleave one Si–C(phenyl) bond from the arylrhodium complex determines the enantioselectivity. The enantioselectivity originates from the silyl moiety extruding from the phenyl ring on the rhodium atom in the reductive elimination transition state.