A stabilizer mixture containing A) either (A1) at least one compound of the formula ##STR1##

in which R₁ is for example hydrogen or C₁-C₈alkyl; R₂, R₃, R₅ and R₆ are for example hydrogen, C₁-C₃₀alkyl or phenyl; R₄ is for example C₁-C₃₀alkyl or 2,2,6,6-tetramethyl-4-piperidyl; and n₁ is a number from 1 to 50; or (A2) at least one compound of the formulae ##STR2##

wherein n₂ and n₂* are a number from 2 to 50;

B) magnesium oxide, magnesium hydroxide, zinc oxide, zinc hydroxide or an organic salt of zinc or magnesium; and

C) either

(C1) an UV absorber or

(C2) a pigment or

(C3) an UV absorber and a pigment;

with the proviso that, when component A) is at least one compound of the formulae (IIIa) and (IIIb), component B) is magnesium oxide, magnesium hydroxide or an organic salt of zinc or magnesium.

Such a stabilizer mixture is particularly useful for stabilizing a polyolefin against light-induced degradation.