Coating compositions are provided which include a polysiloxane comprising at least one reactive functional group and at least one material comprising at least one reactive functional group. Also provided are multi-layer composite coatings formed from a basecoat deposited from a pigmented coating composition and a topcoat applied over the basecoat, the topcoat deposited from the aforementioned coating composition. A method for improving the scratch resistance of a coated substrate, as well as coated substrates also are provided. The compositions of the invention provide highly scratch resistant coatings, particularly highly scratch resistant color-plus-clearcoatings.