The article presents empirical research data collected by the cross-sectional method on a Kazakh sample and aimed at assessing psychological well-being in people of different age groups. The level of psychological well-being was studied by indicators of age and such socio-demographic characteristics as gender, education, family status, presence, absence and number of children, employment, income and sports activity. The analysis of differences in indicators of psychological well-being is carried out: positive relations, autonomy, environmental mastery, personal growth, purpose in life, self-acceptance, affect balance, meaningfulness of life, a person as an open system and an integral scale of psychological well-being. According to the indicators of personal growth and person as an open system, statistically significant differences in gender and age were revealed: in a group of female respondents aged 16-19, these indicators are higher. According to the indicators of environmental mastery and affect balance, statistically significant age differences were revealed among respondents of both sexes of late maturity 41-55 years and pre-retirement age 56-65+ years. Thus, we confirmed the assumption that respondents of different age groups have statistically significant differences in indicators of psychological well-being. We believe that in the context of modern world experience, the study of psychological well-being is relevant, and in Kazakhstan it will acquire a special meaning.