To improve the well-being and health of students, several Dutch schools currently implement health promoting lifestyle interventions. To which degree these interventions influence bullying behavior in the school setting is unknown. This mixed methods study examines the influence of a lifestyle intervention at four primary schools (The Healthy Primary School of the Future; HPSF) on bullying. A longitudinal survey among 6th grade students indicated some decrease in bullying at intervention schools compared to control schools (p = .041). Interviews and focus groups conducted with school staff of the intervention schools reveal a decrease in conflicts between children, which most likely also affects bullying. According to the staff, the structural aspects of HPSF create a safer school environment with less opportunity for conflict behavior. This study demonstrates a possible positive (side) effect of a lifestyle intervention on conflicts and bullying. Further research is needed to confirm these observations.