Key Social Norms Take-aways This study demonstrates that gender-equitable norms—particularly attitudes supporting shared household decision-making, joint family planning decisions, and family planning self-efficacy—significantly influence women’s adoption and sustained use of modern contraceptives in urban Nigeria. Importantly, neighborhood-level gender norms also matter: living in a community where gender-equitable attitudes are prevalent increases the likelihood of contraceptive use and continuation. While attitudes toward wife beating were widespread and largely stable, they did not predict contraceptive use. This suggests that specific dimensions of gender norms, rather than general attitudes toward gender-based violence, are more influential in shaping reproductive behavior. Objectives: To examine how changes in individual and neighborhood-level gender-equitable attitudes influence modern contraceptive use over time among women aged 15–49 living in six Nigerian cities. Methods: A longitudinal, multilevel analysis was conducted using data from 9,933 women surveyed in 2010/2011 and again in 2014 as part of the Measurement, Learning & Evaluation Project. Modern contraceptive use was categorized into four patterns: consistent use, non-use, adoption, and discontinuation. Gender norms were measured through scales assessing attitudes towards wife beating, household decision-making, couples’ family planning decisions, and family planning self-efficacy. Multilevel multinomial logistic regression models were used to assess associations between these attitudes and contraceptive use patterns, controlling for socio-demographic variables. Results: Modern contraceptive use rose from 21% to 32% over the study period. Women who maintained or adopted more gender-equitable attitudes—particularly in household decision-making, family planning decision-making, and self-efficacy—had significantly higher odds of adopting or continuing modern contraceptive use and lower odds of discontinuation. These associations held true both at the individual and neighborhood levels. Attitudes toward wife beating did not significantly predict contraceptive behavior. Variations in gender norms explained up to 61% of the differences in contraceptive use across neighborhoods. Conclusions: Promoting gender-equitable norms at both the individual and community levels can substantially improve uptake and continuation of modern contraceptives. Interventions should focus on enhancing women’s agency in decision-making and increasing community support for shared reproductive responsibilities. Gender-transformative programming, particularly in urban settings, is critical for improving reproductive health outcomes.