This paper examines how interpersonal social networks relate to the voting behavior of men and women. We argue that underlying the gender gap in voting is related to social processes that depend on the partisan and sex composition of networks. Analysis of the 2000 American National Election Study identified two ways that sex differences are relevant to network explanations of voting behavior. First, men have more sex homophily in their networks than women. As men are more likely to be Republican than women, this leads to different discussion environments for men and women. Second, men—and not women—are more likely to share the political opinion of women discussants, but only when they are pro-Bush and the remainder of the network is also supportive. The results support a social model of voting behavior that highlights the importance of social factors (in this case sex) other than just partisan differences.