The purpose of the study was two-fold: to examine the socio-demographic and psychologicalrnpredictors of well-being and formulate a socio-culturally sound approach explaining the meaningrnand experience of psychological well-being among Ethiopian adults. Ryan and Deci’s Self-rnDetermination Theory was duly considered as a theoretical framework of the study. The studyrnfollowed a sequential explanatory mixed method design. Both quantitative and qualitative data werernobtained, via scales and open-ended questionnaires, from 438 civil servants working in Addis Ababa.rn30 interviews were also conducted to gain further information. An in-depth analysis of the reliabilityrnand validity of instruments was made before employing them to the main study. The results showedrnthat adults were better off in both their scores of psychological and subjective well-being. Besides,rnadults’ well-being was found to be quite a function of their gender, age, marital status, educationalrnlevel and household income. Males had a healthier psychological well-being status than females,rnwhere as females were better in their subjective well-being. A significant difference in psychologicalrnwell-being was also observed between emerging and young adults, in favor of the young; andrnbetween cohabitated and married adults, married being advantageous. A significant difference inrnsubjective well-being measures was also noticed among single, cohabitated and married adults, inrnfavor of the married adults in all measures. The finding revealed that happiness level of adultsrndecrease as their educational status increases while the reverse is true to psychological well-being.rnBesides, as adults’ household income boosts, so do their psychological well-being and satisfaction inrnlife. The regression analysis also produced significant independent contributions of householdrnincome to overall well-being of adults. As such, subjective well-being was significantly predicted byrndummy variable of sex and marital status. Likewise, the agreeableness, conscientiousness,rnneuroticism and openness dimensions of personality were notable significant predictors of adults’rnpsychological well-being where as extraversion and agreeableness were significant predictors ofrntheir subjective well-being. Religiosity was also a significant predictor of adults’ psychological well-rnbeing. Besides, adults’ well-being was significantly predicted by the interaction betweenrnconscientiousness and religiosity. From goal pursuit dimensions, attainment of extrinsic life goalsrnwas a significant predictor of both psychological and subjective well-being. Importance andrnattainment of intrinsic life goals also significantly predicts adults’ psychological well-being. Finally,rnthe subjective well-being of adults was significantly predicted by environmental mastery, positivernrelations with others, self-acceptance and overall psychological well-being scores of adults. Thernthematic analysis identified five major categories of themes, which are essential in explaining thernpsychological well-being of Ethiopian adults. These were; socio-cultural harmony, social cohesion,rnsecurity, competence and accomplishment, and the self. Detailed discussion on the rational forrnincluding these themes was made and appropriate implications were proposed. Researchers arernencouraged to expand the findings of this research and in turn develop a suitable approach taping thernpsychological well-being of adults living in countries like Ethiopia