Purpose: This study aims to investigate school principals' well-being by using the job demands-resources (JD-R) model as a theoretical framework. It aims at making a significant contribution to the development of this model by considering not only job demands and job resources, but also the role of personal resources and personal demands as predictors of work engagement and burnout. In particular, it was hypothesised that job demands may mediate the relationship between workaholism and burnout, whereas job resources may mediate the relationship between self-efficacy and work engagement and burnout. Design/methodology/approach: A survey study was conducted. In total, 224 school principals (67 percent women) during training activities completed a questionnaire. Findings: The results of SEM analyses largely supported the hypotheses by showing that personal variables operate as initiators of health impairment and motivational processes. Research limitations/implications: The study lends support to the literature on individual resources that underlines the role that personal resources play in work engagement and burnout. It contributes to the JD-R model by highlighting the role of personal demands (i.e. workaholism), which has an effect on the development of burnout in school principals. Practical implications: The implications of these findings for interventions aimed at the promotion of school principals' well-being are discussed. Originality/value: This study advances the understanding of the role played by personal resources and personal demands in the job demands-resources model. The value added is represented by the study of workaholism as personal demand, which in turn influences job demands and also the health impairment it triggers. (Contains 2 tables and 1 figure.)