Sub-Saharan Africa is experiencing large-scale cultural change. Christianity has spread widely and is now nearly universally adopted by non-Muslim populations. Despite this, traditional spiritual beliefs remain deeply rooted and continue to ground social, economic, and political life. Descriptive accounts– especially by African scholars– suggest that Christianity’s universal doctrine, which posits a single god and a single path to salvation, has had adverse consequences for traditional beliefs. We examine this relationship using data from the DRC and across Africa. Text analyses of sermons reveal that traditional customs and beliefs are frequently mentioned and almost always portrayed in a negative light. Behavioral experiments in the DRC show that individuals known to hold traditional beliefs are treated less prosocially and that antisocial norms and negative stereotypes support this behavior. Such effects are not found for any other characteristic; they appear among all subgroups of our sample; and they intensify with economic development. Patterns in cross-Africa survey data are consistent with the Congolese experimental findings. Finally, consistent with Christianity being a source of these effects, we find that in both the experiments and surveys, the findings are stronger in areas with more exposure to colonial missionary activity.