The synergistic effects of zinc oxide (ZnO) with layered double hydroxides (LDH) in ethylene vinyl acetate copolymer/LDH (EVA/LDH) composites have been studied using thermal analysis (TG), limiting oxygen index (LOI), UL-94 tests, and cone calorimeter test (CCT). The results from the UL-94 tests show that the ZnO can also act as flame retardant synergistic agents in the EVA/LDH composites. The CCT data indicated that the addition of ZnO in EVA/LDH system can greatly reduce the heat release rate. The TG data show that the ZnO can increase the thermal degradation temperature and the charred residues after burning.