A method of improving the adhesion of metathesis compositions, such as ring-opening metathesis polymerization (ROMP) compositions, to a substrate is disclosed, in which an adhesion promoter is added to a polymerizable resin composition in order to improve the adhesion of the polymerizing resin to a substrate material. The addition of the adhesion promoter has been found to provide beneficial improvements in the adhesion of metathesis, especially ROMP, compositions to substrates, particularly glass surfaces, leading to improved characteristics in ROMP materials formed therefrom. The adhesion promoter generally comprises a functionalized silane compound and a peroxide compound. A ROMP composition is further disclosed comprising a cyclic olefin, a ROMP metathesis catalyst, and the adhesion promoter.