Aim: This study explores the association between the psychosocial work environment in school and students’ somatic health complaints. With its point of departure from the Demand–Control–Support (DCS) model, the aim was to examine how aspects of decision control and social support can moderate stress-related health implications of high psychological demands. Methods: Data come from two cross-sectional waves of the Swedish version of Health Behaviour in School-aged Children (HBSC 2005/2006 and 2009/2010), which consists of a total of 9427 11-, 13- and 15-year-old students. A two-level random intercept model was applied, with school class as the level 2 unit. Results: Findings showed significant associations between school demands and somatic health complaints for all studied age groups, with a slight increase in strength with age. Decision control as well as social support from teachers, parents and peers consistently predicted a favorable association with health. An age pattern emerged in the analyses of stress-moderating resources. For 11 year olds parental support was the only resource that displayed a significant interaction with demands in relation to somatic health complaints, whereas for 13 year olds, decision control and support from teachers and parents all demonstrated moderating effects on student health. For 15 year olds, however, it was peer support that acted as a buffering resource in the studied relationship. Conclusions: The psychosocial work environment is an important predictor of students’ health complaints. Overall, social support was a better stress-moderating resource than decision control, but some "buffers" were more important at certain ages than others.