A flame retardant additive for polymers is disclosed which additive comprises a polyacrylate in combination with a) at least one zinc borate, b) at least one silicone resin, and c) alumina trihydrate or magnesium hydroxide or a mixture thereof, said additive being free of halogens, antimony oxide and phosphorus-containing substances. A flame retardant composition comprising a polymer and a flame retardant additive is also disclosed as well as a method of reducing the flammability of a polymer by mixing said polymer with said flame retardant additive.