Our study drew on original data collected in Durham, NC, and four sending communities in Mexico to examine differences in women's relationship power that are associated with migration and residence in the United States. We analyzed the personal, relationship, and social resources that condition the association between migration and women's power and the usefulness of the Relationship Control Scale (RCS) for capturing these effects. We found support for perspectives that emphasize that migration may simultaneously mitigate and reinforce gender inequities. Relative to their nonmigrant peers, Mexican women in the United States average higher emotional consonance with their partners, but lower relationship control and sexual negotiation power. Methodologically, we found that the RCS is internally valid and useful for measuring the impact of resources on women's power. However, the scale appears to combine diverse dimensions of relationship power that were differentially related to migration in our study.