Despite the fact that corporal punishment (CP) is a significant risk factor for increased aggression in children, child physical abuse victimization, and other poor outcomes, approval of CP remains high in the United States. Having a positive attitude toward CP use is a strong and malleable predictor of CP use and, therefore, is an important potential target for reducing use of CP. The Theory of Planned Behavior suggests that parents' perceived injunctive and descriptive social norms and expectations regarding CP use might be linked with CP attitudes and behavior. A random-digit-dial telephone survey of parents from an urban community sample (n = 500) was conducted. Perceived social norms were the strongest predictors of having positive attitudes toward CP, as follows: (1) perceived approval of CP by professionals (β = 0.30), (2) perceived descriptive norms of CP use (β = 0.22), and (3) perceived approval of CP by family and friends (β = 0.19); also, both positive (β = 0.13) and negative (β = -0.13) expected outcomes for CP use were strong predictors of these attitudes. Targeted efforts are needed to both assess and shift the attitudes and practices of professionals who influence parents regarding CP use; universal efforts, such as public education campaigns, are needed to educate parents and the general public about the high risk/benefit ratio for using CP and the effectiveness of non-physical forms of child discipline.