In various embodiments, the present invention provides a tooth whitening composition comprising a peroxide composite and an orally acceptable carrier. The peroxide composite comprises a peroxide compound and a porous cross-linked polymer, preferably in the form of a microporous particulate. The peroxide compound can be sorbed onto the porous crosslinked polymer. The porous cross-linked polymer may comprise a polymerized polyunsaturated monomer selected from polyacrylates, polymethacrylates, polyitaconates, and mixtures thereof. The carrier can be non-aqueous, and can comprise a film forming material. Methods are also provided for whitening a tooth surface with the tooth whitening compositions.