Cross-cultural studies on the relationship between subjective and psychological well-being in children are still very limited. Consequently, proposing a model that considers the interaction of these constructs and examining its applicability in several countries would enhance the understanding of these phenomena in childhood. Thus, the objective of this study is to identify the latent relationship between subjective and psychological well-being, and to measure invariance in a sample of 12-year-old children from 30 countries. Through a quantitative methodology with a correlational design, we analyze data from 44,358 children who participated in the third wave of the International Survey of Children’s Well-Being (ISCWeB), using Structural Equations Modeling (SEM). Results suggest that levels of subjective and psychological well-being are moderate and high, respectively, and point to significant differences in well-being indicators by country. In addition, subjective well-being is related to psychological well-being through a general adjustment model with oblique factors. Finally, the model of latent relationships presents metric invariance across nationalities.