<p>This study examines the gender norm that “a wife should not earn more than her husband” and its impact on women’s labor market behavior in a traditional, developing country context, using ten annual waves of Household Labor Force Statistics data from Türkiye (2014–2023) covering 1,053,258 couples. The study first analyzes the distribution of wives’ relative income—the share of a couple’s income earned by the wife—using regression discontinuity analysis, addressing a gap in empirical research on gender identity and economic behavior in emerging economies. Results reveal a sharp drop at the threshold where the wife’s income exceeds her husband’s, indicating that couples tend to avoid such scenarios. Second, to examine wives’ labor force participation and the gap between actual and potential earnings, generalized linear models and a quantile-based approach are applied, offering a methodological contribution in this context. Findings show that the probability of a wife out-earning her husband significantly reduces her likelihood of labor force participation. Wives earning below their potential are more likely to adjust their earnings downward, while high-earning wives appear less constrained. Although the influence of gender identity norms has weakened over time in relative income and participation, its impact on the income gap has intensified, highlighting a growing divide between lower- and higher-earning women. Promoting gender-equal attitudes, expanding women’s employment opportunities, and providing targeted training programs for low-income women would help reduce the persistence of traditional gender norms in Türkiye’s labor market.</p>