This paper investigates how childhood housing conditions shape long-term educational outcomes, with particular attention to gender disparities. Drawing on full-count microdata from the 2015 Chinese population census and historical housing exposure from 2010, we construct a county-level dataset to examine high school completion rates among adolescents aged 15-19—a critical transition beyond compulsory education. We find that improved housing conditions—such as larger per capita floor space and better access to basic facilities—are significantly associated with higher rates of high school completion. Our estimates are robust to controls and an instrumental variable (IV) model approach using housing conditions in neighboring counties. We further analyze longitudinal panel data from approximately 3,000 individuals in the China Family Panel Studies (CFPS), tracking their trajectories from adolescence (2010) to adulthood (2022). We show that adolescents who lived in crowded homes—defined as having less than 20 square meters of living space per capita—attain fewer years of schooling by adulthood. This negative effect is particularly pronounced among girls with male siblings in overcrowded households, who face up to 2.4 fewer years of schooling. This study extends the literature on environmental influences on educational outcomes and intergenerational mobility, by showing that not only neighborhood context, but also home-level housing conditions constitute a form of environmental inequality that shapes long-term educational trajectories.