We use the 2015 Canadian time diary data to examine the gender income gap in relation to time spent doing domestic (household and childcare) and market work. Specifically, we highlight the impact of relationship and parenting status by comparatively examining three groups: single without children, married without children, and married with children (N = 10,573). After controlling for household labour and market work hours, we find that the gender income gap is negligible for those who are single without children. The gender income gap for married couples without children is much larger. The largest gender income gap exists for married couples with children. When we examine married couples with children, accounting for hours spent on market and domestic work reduces the gap substantially. There is a mediating relationship of market work to the domestic work-income relationship. Domestic work is the largest contributor in the models predicting market work hours. We contribute to the understanding of gender-based income inequality by going beyond the conventional study of market work. Implications for reducing structural gender inequality in income by addressing both family and work spheres are discussed.