This study explores the determinants (demographic, personal, behavioural, and social) by which happy and unhappy people differ. The primary sample from which the participants were chosen was a representative sample of Croatian citizens (N = 4000). On the basis of the distribution of overall happiness the sample of the highest (the happy group) and the lowest 10 % of participants (the unhappy group) were selected. The happy group (N = 400) represented the upper end of the happiness distribution, while the unhappy group (N = 400) represented the lower end of the distribution. The questionnaire included demographic characteristics (age, gender, income, and education), ratings of subjective health status, satisfaction with specific personal and national domains (IWI-International Wellbeing Index), trust in people, and trust in institutions. Frequency of various leisure activities, and involvement in the community life were also reported. The differences in examined variables were analysed between the two groups. Results showed that the happy individuals were younger, with higher income, and with higher education than unhappy ones. After controlling for age, income, and education level, the happy people were found to be more satisfied with personal and national wellbeing domains, of better subjective health status, reported higher trust in people and institutions, and were more engaged in leisure activities and community life than the unhappy ones.