How do subjective socioeconomic status (SES) and departmental identity promote the mental health of female undergraduates? We conducted a questionnaire study (Study 1) and an experimental study (Study 2) with undergraduates enrolled in a women's junior college to examine whether subjective SES and group identity have an interactive effect on mental health. Results indicated that in participants with high subjective SES, increased identification with their reference in-group (the academic department) was associated with a decreased tendency for depression (Study 1). These individuals also showed reduced negative affect when responding in situations of social exclusion (Study 2). These effects were absent, or had a reduced intensity in participants with low subjective SES. In sum, subjective SES and departmental identity interact to reduce depressive tendencies and negative affective responding for female undergraduates. Individuals with higher subjective SES may gain more benefits from group identity. We have discussed the implications of these findings.