Gender norms are increasingly recognized as important modifiers of health. Despite growing awareness of how gender norms affect health behavior, current gender norms scales are often missing two important theoretical components: differentiating between descriptive and injunctive norms and adding a referent group. We used a mixed-methods approach to develop and validate a novel gender norms scale that includes both theoretical components. Based on qualitative data, the theory of normative social behavior, and the theory of gender and power, we generated a pool of 28 items. We included the items in a baseline questionnaire among 3,110 women in Odisha, India as part of a cluster randomized controlled trial. We then ran exploratory factor analysis which resulted in 18 items. Using a second wave of data with the same sample, we evaluated psychometric properties using confirmatory factor analysis and structural equation modeling. The analysis resulted in two subscales with nine items each, “descriptive gender norms” and “injunctive gender norms.” Both subscales represent high internal validity with Cronbach’s alpha values of 0.81 and 0.84 and the combined scale has an alpha of 0.87. The G-NORM, gender norms scale, improves on existing measures by providing distinct descriptive and injunctive norms subscales and moving beyond individual attitudes by assessing women’s perceptions of community-level gender norms.