Having an imaginary companion (IC) is a fascinating example of children's imaginative and pretend play. However, there are inconsistencies in the reported prevalence of children's ICs. This study examined how culture may affect this prevalence. We conducted a meta-analysis to assess whether the culture, as well as age, assessment method, sex, and birth order, may affect the prevalence of ICs in studies that included children under age 12. The results revealed that culture, as well as assessment method and sex/birth order, may have a significant impact on the prevalence of ICs. Specifically, children in Western cultures were more likely to report invisible friends as compared to children in Japan, but the total prevalence of ICs did not differ across cultures. We illustrate several implications for future research on ICs.