This cross-sectional study aimed to examine the associations of sex, age, marital status, education attainment, religious involvement, perceived health, and income with psychosocial domains of wellbeing assessed using the Geriatric Depression Scale (GDS-15), Satisfaction with Life Scale (SWLS), Subjective Happiness Scale (SHS), and Spiritual Wellbeing Scale (SWBS). In total, 356 community-dwelling older adults from Greece, aged 65 years and above, completed a sociodemographic survey and psychosocial self-reported questionnaires. Bivariate and stepwise regression analyses helped to determine the sociodemographic factors' associations with their wellbeing. These background predictors together explained a significant part of the variance in scores on all psychosocial domains: 31% for GDS-15, 44% for SHS, 63% for SWLS, and 58% for SWBS. After controlling for other sociodemographic factors, both being healthy and attending church were related to better outcomes in the domains of happiness, life satisfaction, and spiritual wellbeing. Higher income was related to better outcomes on all domains of wellbeing, while higher educational attainment was related to worse outcomes on all domains of wellbeing. Marital status was positively related to depression only. Thus, successful aging approaches may benefit from a deeper understanding of wellbeing and its predictors, which are essential to improve older adults' psychosocial wellness.