Entrepreneurial intentions determine to a large extent the entrepreneurial behavior; therefore, the study of those intentions and the factors that influence them constitute a valid research area. The purpose of this regional comparative study was to design a new causal model of the formation of the entrepreneurial intention among young adults in Spain and Poland. Using the Structural Equation Modeling (PLS) methodology, the results show that subjective variables (beliefs, social norms, values) initiate the chain of effects that influence the action variables (motivation, self-efficacy, intention). Attitude is the nexus variable between both groups of variables. It is verified that there are no significant differences in the responses to the items or in the causal relationships of the model between both countries. This confirms the relevance of a homogenizing generational approach at a global level that allows the application of policies to promote the entrepreneurial intention for the entire segment. The proposed model takes into account and complements the previous designs, and is practical because it can be used at different levels of the education sector and by institutions promoting entrepreneurship and sustainability.