The COVID-19 pandemic, which started in Wuhan, China, has been moving around the world since late 2019. In Indonesia, the first case of a Covid-19 patient was identified on 2 March, 2020, in Depok. For now (30 July, 2021), confirmed cases in Indonesia had reached 3,372,374 cases, and 92,311 of them died. Therefore, preventive measures are needed so that the chain of Covid-19 spread in Indonesia is broken, one of which is vaccination. For now, Indonesia is in the process of accelerating vaccination coverage. It has been given to people in the 12-17 year age group, the majority of which are in high school (SMA). Based on SDGs point 4, namely quality education, especially in the field of basic education. Educational steps were taken for the community, especially high school students in several schools in Indonesia, by making online counseling activities and seeing an increase in students' understanding of knowledge related to Covid-19 vaccination. Before the counseling begins, participants will be given a questionnaire in the form of a pre-test to determine the knowledge of high school students before the counseling. After the counseling is carried out, the counseling participants will also be given a post-test to see if there is an increase in the knowledge of high school students regarding the Covid-19 vaccination. In this study, there were 157 respondents who filled out the pre-test and post-test. The results of this study showed that there was an increase in students understanding of Covid-19 vaccination after online counselling.