This study set out to explore levels of religious affect (measured by the Francis Scale of Attitude toward Christianity) and personal affect (measured by the Oxford Happiness Questionnaire) among samples of Catholic students in the Republic of Ireland attending fifth- and sixth-year classes (N = 3015) and Catholic students in Northern Ireland attending sixth-form classes (N = 1624), after taking into account individual differences in sex, age, and personality (as measured by the abbreviated form of the Eysenck Personality Questionnaire Revised). Consistent with the findings of previous research, the data demonstrated a significant positive association between religious affect and personal happiness: religious students are happier students. Catholic students in Northern Ireland hold a more positive attitude toward Christianity (higher levels of religious affect) than Catholic students in the Republic of Ireland. Nonetheless, there is no significant difference in levels of happiness (personal affect) between Catholic students in the two jurisdictions.