This study investigated the factorial structure and invariance of the Mental Health Continuum-Short Form (MHC-SF) across cultural groups from three nations, namely, the Netherlands, South Africa, and Iran (N = 1120). The three-dimensional structure of mental well-being was supported in all the groups. The results of measurement invariance testing confirmed the full metric and partial scalar invariance of the MHC-SF. The study also compared the latent means for the aspects of mental well-being in the three cultural groups, and found significant differences. The significance and implications of the results are discussed.