The preparation and deesterification of a number of polymers and copolymers of unsaturated tetrahydropyranyl esters has been studied. The conditions required to remove the tetrahydropyranyl group from these esters are extremely mild. Hence it is possible to use dihydropyran as a protecting group in the preparation of polymers containing other groups susceptible to normal hydrolysis conditions. The reactivity ratios for the tetrahydropyranyl methacrylate/styrene and tetrahydropyranyl acrylate/styrene copolymerization systems have also been determined.