Ensuring and expanding women’s agency is an essential component of efforts to promote the rights and well-being of women. However, inadequate measurement hampers monitoring and research into achieving this goal. In this study, we developed a theory-based measurement tool of women’s agency. We developed a conceptual model of agency through a review of the literature, and then used this model to identify potential indicators of agency. These indicators were asked as part of a population-based household survey that was completed between July and November 2016 by 3042 women in rural Rajasthan, India. We tested the construct validity of the hypothesized measurement model using confirmatory factor analysis. We identified a conceptual model of agency, composed of 23 indicators, which measured the domains Household Decision-Making, Freedom of Movement, Participation in the Community, and Attitudes and Perceptions. This conceptual model fit the study data well (CFI = 0.974, TLI = 0.970, RMSEA = 0.031). Our results have implications for measurement efforts in a number of settings, and our tool can be used to measure women’s agency in rural India. o̧pyright 2018, p̧yright 2018 Human Development and Capability Association.