The attractiveness of regions and territories for firms, investments, tourists, students, talented people, and other categories is a relevant issue for regional economic development, due to the increasing importance of the relationships and flows on the global scale. The growing concern about this question requires a new comprehensive analytical approach that goes beyond partial approaches. The construction of a synthetic index that measures the territorial attractiveness from a multidimensional perspective is the strategy presented in this work to deal with this issue from a new point of view. We first introduce and present our methodological approach for the construction of the synthetic index, which makes use of both qualitative (budget allocation process) and quantitative (factor analysis) techniques. Our synthetic index is based on the main indicators about incoming flows from abroad (FDIs, workers, tourists, university students). Secondly, we illustrate and discuss the results of its application to the case of the international attractiveness of the Italian regions, based on an 8-year long dataset. The findings reveal that the North–South gap, the well-known Italian spatial pattern, is not fully satisfying to read and interpreter the geographical imbalances in terms of multidimensional territorial attractiveness. Thanks also to the calculation of the Moran’s Index, we show the complexity of the Italian economic geography.