This review covers the contributions of cognitive trainings to stability in cognitive, everyday, and brain functioning across adulthood. For these functional domains, relevant types of empirical evidence were defined for training-induced enhancement in absolute, differential, and dimensional stability in the light of developmental decline. The state of research regarding these types of evidence is presented. Little data were generally available on the effects of cognitive trainings on the stability of everyday and brain functioning and across all covered domains for their contributions to differential stability. There was sound empirical support for training-induced en- hancements of absolute and dimensional cognitive stability across adulthood. The theoretical, methodological, and practical implications of these findings are discussed.