The dataset contains data from 26 studies on cross-linguistic influence at the level of morphosyntax in simultaneous and early sequential bilingual children. Calculated effect sizes were used in the following study: van Dijk, C.N., van Wonderen, E., Koutamanis, E., Kootstra, G.J., Dijkstra, T., & Unsworth, S. (to appear). Cross-linguistic influence in early bilingual children: A meta-analysis. Journal of Child Language. A short description and coding decisions for each study in the dataset are included.