In a panel study, the relationship between Emotional Stability (ES), Extraversion (E) and Subjective Well-Being (SWB) was tested against questionnaire data from 264 Norwegian folk high school students. After a careful reading of recent studies concerned with relationships between personality and subjective well-being, it was hypothesized that the effect from ES on SWB indicators (Life Satisfaction, presence of Positive Affect and absence of Negative Affect) is stronger than the corresponding effect from E. Moreover, it was anticipated that if ES was controlled for, the effect from E on SWB would decrease substantially. In several multiple regression analyses, it was found that, on average, the amount of SWB variance accounted for by ES was 34%, while similar figures for E were 1%. The results are discussed with reference to cultural values and traditions.