While the high savings rate in China has global impact, existing explanations are incomplete. This paper proposes a competitive saving motive as a new explanation: as the country experiences a rising sex ratio imbalance, the increased competition in the marriage market has induced the Chinese, especially parents with a son, to postpone consumption in favor of wealth accumulation. The pressure on savings spills over to other households through higher costs of house purchases. Both cross-regional and household-level evidence supports this hypothesis. This factor can potentially account for about half of the actual increase in the household savings rate during 1990-2007.