The gun ownership literature is vast, with dozens of studies seeking to explain who owns guns and why. We build on this literature in two key ways. First, we introduce a new variable into the fold: moral concern about harming others. We theorize that this concern actively inhibits gun ownership. Second, we direct theoretical and empirical attention to a predictor of gun ownership that has frequently been overlooked in the contemporary gun literature: childhood socialization. Using data from a national sample of 1,100 adults, we find that moral concerns about harm represent a barrier to gun ownership and limit the number of guns people own. By contrast, childhood socialization has the opposite effect. Furthermore, we find that childhood socialization is not only the strongest predictor of owning guns but also fully mediates the relationship between gender and gun ownership.