This study synthesizes quantitative research on the relationship between creativity and bilingualism. Extant literature underlines the role of developmental, cognitive, and socio-cultural factors to explain the nature of the relationship between creativity and bilingualism. While decades of research frequently indicate a positive link, contrary or mixed evidence has also been documented, necessitating a comprehensive analysis of existing quantitative data to understand the direction and strength of this relationship. Additionally, identifying factors contributing to inconsistent outcomes is crucial. Thus, we estimated the mean effects and examined various potential sources of variation, including study and participant characteristics, as well as measurement and bilingualism-related factors, to shed light into the heterogeneity. Addressing these objectives, we analyzed 312 effect sizes from 39 studies (N = 4,917) and found a mean effect size of Pearson r = 0.181, 95% CI [0.096, 0.263]. This finding shows that bilinguals are overall more creative than monolinguals. Furthermore, a significant difference was observed in the mean effects between test modality categories, with studies using numerical modality reporting significantly larger effect sizes compared to those using action/movement modality. We discuss the findings with research and practical implications.