By Aug 10, 2022, 3 497 208 of the estimated 4·4 million adults living in Scotland had received three doses of a COVID-19 vaccine. However, a proportion of the adult population remains unvaccinated (defined as no record of any vaccine being administered) and susceptible to severe COVID-19 outcomes. Characterising this population can help to understand gaps in vaccine coverage and determinants of vaccine hesitancy and could support targeted public health messaging. Unlike the vaccinated population, on whom information is gathered at the point of vaccination, current estimates of the unvaccinated population are calculated using general practitioner (GP) records.