Communalizing colonial policies (CCPs) include a variety of practices that recognize and institutionalize communal difference among colonized populations, and several qualitative analyses find that they promoted postcolonial ethnic conflict. In contrast, the few quantitative analyses that explore this issue focus on several mechanisms, make conflicting claims, and provide mixed results, thereby suggesting that CCPs do not have general effects. Yet the quantitative findings might be inaccurate for several reasons: Some use the identity of the colonizer as a proxy for CCPs, others measure a CCP but have small samples with limited variation in the focal independent variable, and all of these analyses are unable to explore whether CCPs affect ethnic conflict through different and competing mechanisms. To address these limitations, we create four ideal types of CCPs, gather data on a CCP that conforms to each ideal type, and test the relationships between CCPs and ethnic civil warfare onset using the set of former British and French colonies. We find that a discriminatory CCP is associated with high odds of ethnic civil war onset, especially shortly after independence. Alternatively, differentiating and accommodating CCPs lack general relationships with ethnic civil war onset, and an empowering CCP is negatively related to ethnic warfare in most models.