The synthesis of new types of stabilizers (a combination of 2,2,6,6-tetramethylpiperidine and 2-hydroxyphenylbenzotriazole in one molecule) is reported. Six polymerizable combined stabilizers as well as two unsaturated triazinyl-2,2,6,6-tetramethylpiperidines and three unsaturated triazinyl-2-hydroxyphenylbenzotriazoles as individual stabilizers were synthesized. Their copolymers and the terpolymers of the individual stabilizers with methyl methacrylate were obtained. Chemical bonding of the stabilizers in the polymer was confirmed spectrophotometrically. The influence of these additives on the photostability of the copolymers was studied. The participation of the combined stabilizers in the polymerization did not affect considerably the rate of copolymerization, the molecular weight and polydispersity of the copolymers. A significant stabilizing effect against photodegradation was determined.