Within comparative school effectiveness research facilitated by large-scale data across countries, this article presents the results of the testing for measurement invariance of the latent concept of Professional Community (PC) across 23 European countries and more than 35,000 teachers in secondary schools. The newly proposed Multiple-Group Factor Analysis Alignment method is applied to obtain the mean differences of the latent PC factor, while also identifying the non-invariant parameters in these different countries. After performing a number of robustness checks, including the Multiple-Group Confirmatory Factor Analysis (MGCFA) exact scalar method, we conclude that teachers in Eastern European countries report the highest average perceived PC practices. The countries with smaller PC mean differences tend to shift places in the ranking when the 2 methods are applied; however, very few changes among the groups with significant latent mean differences are observed.