An unprecedented Co(III)-catalyzed stereoselective C–H homoallylation reaction of indole derivatives with 4-vinyl-1,3-dioxan-2-ones to access (E)-homoallylic alcohols has been developed. This protocol features mild reaction conditions, high efficiency, good yields, excellent stereoselectivity, and a broad tolerance towards a variety of functional groups. Notably, the reaction provides a powerful approach for the late-stage C–H homoallylation of indole-based substrates, including bioactive indole derivatives and pharmaceutically relevant indole-containing molecules.