Résumé : This vignette-based study examined in a sample of unvaccinated Belgian citizens (N = 1918; Mage = 45.99) how health care workers could foster reflection about and intentions to get vaccinated against COVID-19 by experimentally varying their communication style (i.e., autonomy-supportive vs. controlling) and the reference to external motivators (i.e., use of a monetary voucher or corona pass vs. the lack thereof). Each participant was randomly assigned to one of six conditions and rated a vignette in terms of anticipated autonomy satisfaction, perceived effectiveness, reflection, and vaccination intention. An autonomy- supportive, relative to a controlling, communication style predicted greater autonomy need satisfaction, which in turn related positively to perceived effectiveness, reflection, and vaccination intention. External motivators failed to generate positive effects compared to the control condition. The findings highlight the critical role of autonomy support in promoting a self-endorsed decision to get vaccinated.