Compensatory health beliefs, a self-defence strategy, were examined in a theory-guided intervention promoting influenza vaccination at the workplace. In total, 851 employees were randomised to one group aimed at enhancing intention formation (standard group) or to another one assisting self-regulation (intervention group). Assessments took place after the intervention and 5 months later, investigating whether the intervention would interfere with compensatory health beliefs. The intervention generated an indirect effect via planning on vaccination. Compensatory health beliefs mediated between intention and behaviour. An interaction between intervention group and compensatory health beliefs on behaviour transpired. At low compensatory health belief levels, the intervention group resulted in more vaccinations than the standard group.