Understanding distinctions between morality and conventions is an important milestone in children’s moral development. The current meta-analysis integrated decades of social domain theory research (Smetana, 2006; Turiel, 1983) on moral and conventional judgments from early to middle childhood. We examined 95 effect sizes from 18 studies (2,707 children; Mage = 7.30 years; 51% females; 42% Whites). Along with these, effects from additional 28 studies were estimated with imputed correlations in a secondary analysis of 248 effect sizes from 46 studies (4,469 children; Mage = 7.34 years; 46% females; 32% Whites). Across all judgments, moral/conventional distinction effects were significant, positive, and moderate. Consistent with social domain theory definitions of morality, children evaluated moral transgressions as more wrong independent of authorities’ commands or rules than conventional transgressions and moral rules as more generalizable and inalterable than conventional rules. Moral transgressions also were seen as more unacceptable and more deserving of punishment than conventional transgressions. The aggregated effects were also significant for each type of judgment. However, effects were stronger for criteria considered definitional of the domains than for acceptability or punishment judgments, which are not considered criteria. Moreover, children made greater domain distinctions with age across all types of judgments. When examined separately, age moderated effects only for criterion judgments, not for acceptability or punishment judgments. Effects for distinctions also were moderated by the types of moral and conventional rules assessed. Thus, moral/conventional distinctions were found across early and middle childhood, but there was variability in children’s developing understanding.