The aim of the present study was to examine the role of the focus on self-development for the psychoemotional wellbeing of older adolescents (N = 146) and adults (N = 160). Two integrative indicators of the harmonicity / inharmonicity of the focus on self-development are suggested: the ratio of the importance of personal growth to its achievement (realization) and the ratio of the importance (external motivation) of self-development in life spheres to interest (internal motivation) in it. The research revealed that the psycho-emotional wellbeing of adolescents is of hedonistic nature, whereas that of adults is of eudemonic one. With regard to the focus on self-development, the level of the importance of personal growth and the level of its realization in adolescents and adults do not significantly differ. In addition, in both groups the level of the importance is significantly higher than the level of achievement, which indicates an aspiration for further self-improvement. The level of the importance of self-development in different life spheres and the level of interest in it are significantly higher in adults than in adolescents. The harmonious ratio of the importance of self-development to the interest in it and the harmonious ratio of the importance of personal growth to its achievement are most favorable for the psycho-emotional wellbeing of adolescents, while the realization in the sphere of personal growth and their own interest in selfdevelopment are of greater importance for the psycho-emotional wellbeing of adults. In adulthood indicators of the focus on self-development appear to be predictors of components of psycho-emotional wellbeing more often and with greater explanatory power than in the adolescent period. Evaluation of achievements in personal growth and internal motivation for self-development (interest in it) are the strongest predictors of psycho-emotional wellbeing for adults, whereas for adolescents the most important predictor of psycho-emotional wellbeing is the recognition of the importance of personal growth, which can be considered a reference point for the future life.