This paper studies the cultural roots of parental behavior concerning children’s human capital. We examine the effect of traditional kinship norms on parental investment in children’s human capital, with a focus on two predominant forms of kinship norms in developing countries –matrilineal and patrilineal systems. We use novel survey data from Tanzania to capture detailed parental investment behavior, including time and attention devoted to children’s learning. Using a fuzzy spatial regression discontinuity design, we find that matrilineal parents invest less in their children’s human capital. For instance, they are less inclined to check their children’s homework or discuss their children’s performance with teachers. In turn, children from matrilineal backgrounds exhibit lower cognitive skills, captured by standardized test scores in numeracy and literacy. Assessment of various factors suggests that spousal conflict and cooperation, family instability, and labor market conditions are possible mechanisms. Lastly, we evaluate the impact of a nation-building reform designed to challenge ethnic norms. Our findings reveal that this policy failed to effectively counteract the influence of traditional norms.