The COVID-19 pandemic has forced many governments to impose social distancing measures upon its citizens, including in the Netherlands. Motivating adolescents to adhere to measures such as social distancing can be challenging, since adolescents are relatively more affected by them, while experiencing virtually no personal health benefit. In addition, the COVID-19 pandemic seems to impact the social environment of adolescents in schools, as some media sources have reported bullying and stigmatisation of students with an Asian appearance. This study aims to explore the experiences of adolescents regarding their Health-Protective Behaviour (HPB), as well as the prevalence and expression of stigma towards ethnic minorities within the context of the first wave of COVID-19 pandemic. We performed a cross-sectional mixed-methods study, including two independent online questionnaires. An adapted version of the "HPB"questionnaire (n = 528) and the "Measure of Disease-Related Stigma (MDRS)"questionnaire (n = 380), were administered to Dutch adolescents of 10-16 years old, attending primary or secondary school. Furthermore, 15 interviews were held with eight male and seven female adolescents. All data collection took place between March 17 and April 20, 2020. Results show that adolescents perceive COVID-19 as a threat to other peoples' health, rather than their own, and report adherence to public health measures in the interest of older and more vulnerable members of their community. We found no convincing evidence for widespread misinformation or stigmatising of certain ethnic groups among adolescents related to COVID-19 during this study. Participants acknowledged such behaviour happened in the early stages of the pandemic, before this study was initiated. Adolescents are a vital group for public health researchers to engage with during a pandemic, even when reaching them can be challenging.