This paper examines the role of asymmetry in all-pay auctions. In particular, this paper decomposes a change in players’ valuations into the absolute change and the relative change, and analyzes how these changes affect total expenditures. An increase in the sum of players’ valuations increases total expenditures but an increase in asymmetry among players’ valuations tends to decrease total expenditures under both complete and incomplete information. This paper also studies the optimal all-pay auction design problem.