An amine-promoted three-component radical selenofunctionalization reaction of alkenes with TBHP and diselenide is disclosed. The reaction conditions are mild and suitable for a wide range of substrates (29 examples), and all give the corresponding hydroxyselenenylation products in moderate to excellent yields. In addition, preliminary studies on the mechanism reveal that the current method might proceed via a radical pathway. TBHP serves as both radical initiator and the source of hydroxyl group.