Background. Given the scarcity of empirical research on women's friendship in adulthood, it is particularly relevant to examine its understudied aspects. Despite the recognized role of friendship as a factor in subjective well-being, the specifics of its age-related dynamics and its contribution to the quality of life of adult women have remained virtually unexplored in Russian psychology.

Objective. To examine differences in the qualitative characteristics of friendship and subjective well-being between young and middle-aged women, and to explore the associations between friendship functions and indicators of subjective well-being.

Study Participants. The study involved 152 women divided into 2 age groups: young women (n = 90, aged 18–35) and middle-aged women (n = 62, aged 36–55).

Methods. A multimethod approach was employed, including the Life Satisfaction Index (LSI, adapted by N.V. Panina); the Subjective Well-Being Scale (G. Perrudet-Badoux, et al., adapted by M.V. Sokolova); the McGill's Friendship Questionnaire (adapted by A.A. Nesterova) assessing six dimensions of friendship — reliable alliance, stimulating companionship, intimacy, self-validation, emotional security, and help; and an author-developed questionnaire on friendship characteristics. Data were analyzed using descriptive statistics, independent samples t-tests, and Pearson correlation coefficients.

Results. A significantly higher level of subjective well-being was observed in the sample of adult women: they reported greater interest in life, a more positive emotional tone, better alignment between goals and their attainment, and lower levels of psycho-emotional distress. At the same time, no significant age-related differences were found in friendship characteristics — its functions (reliable alliance, stimulating companionship, intimacy, self-validation, emotional security, and help) were perceived similarly across age groups. Friendship quality was positively associated with well-being, with a particularly strong link between self-validation in friendship and life satisfaction, self-esteem, and mood, as well as between all friendship functions and goal-directed persistence.

Conclusions. The functions of women's friendship demonstrate emotional invariance across adult life stages. Their contribution to subjective well-being is realized primarily through affiliative and identity-related mechanisms such as reliable alliance, emotional security, and self-validation rather than through instrumental support. Friendship thus functions as a stable psychological resource, critically supporting women's self-identification, goal-setting, and emotional resilience. The obtained results highlight the necessity of accounting for the specific characteristics of women's friendship in practice-oriented support programs.