The private provision of public goods generally suffers from two types of efficiency failures: sorting problems (the wrong individuals contribute) and quantity problems (an inefficient amount is provided). Embedding the provision game into a contest that rewards larger contributions with higher probabilities of winning a prize may remedy such failures. Applications include tenure decisions at universities, electoral competition among politicians, etc. We identify a tradeoff between the value of the prize and the decisiveness of the contest. High-powered incentives in contests may cause an overprovision of the public good or wasteful participation of unproductive individuals in the contest.