Recent studies have documented substantial penalties associated with motherhood and suggest that discrimination plays an important role in producing them. In this article, I argue that the degree to which motherhood is conceptualized as a choice affects the penalties associated with making this choice. Two methods are employed to evaluate this argument. The first method is an analysis of state differences in the wage penalties for motherhood, in which hierarchical linear modeling is used with data from the 1988–2004 Current Population Survey. The second method is a hiring experiment in a highly controlled setting. The wage analysis shows that, net of the usual individual and state-level factors that affect wages, mothers are penalized more in states where motherhood is perceived to be a woman's choice. The hiring experiment distinguishes between productivity-based and discrimination-based explanations for the penalty and provides strong evidence for a causal relationship between perceptions of choice and discrimination against mothers.