The health of an individual depends on how well he or she can handle various stressors in his or her environment. One vulnerable period occurs during the transition from child to adult. The overall aim of this research project was to determine whether differences in the ability to deal with stress are related to various health indicators, aggression, and school marks during primary and upper secondary school. Data were collected class-wise and 253 Swedish upper secondary school pupils participated. Three well-established questionnaires [Sense of Coherence (SOC), Coping Resources Inventory (CRI) and Aggression Questionnaire (AQ)] were used. In addition, blood pressure, teacher evaluation and school marks were collected. Some demographic data such as gender, age and type of study programme were also collected. Both SOC and Coping Resources Inventory correlated significantly positively with many of the primary and upper secondary marks, while the AQ had significantly negative correlations with the mark. Females obtained higher values than males in Coping Resources Inventory, but lower in SOC and AQ.