By integrating several modeling methods, we find considerable contributions of foreign anthropogenic emissions to surface ozone over China (2–11 ppb). For anthropogenic ozone over China, the foreign contribution is 40–50 % below 2 km and 85 % in the upper troposphere. For total foreign anthropogenic ozone over China, the portion of transboundary ozone produced within foreign emission source regions is less than 50 %, with the rest produced by precursors transported out of those source regions.