Objectives: Belgium experienced multiple COVID-19 waves that hit various groups in the population, which changed the mortality pattern compared to periods before the pandemic. In this study, we investigated the geographical excess mortality trend in Belgium during the first year of the COVID-19 pandemic. Methods: We retrieved the number of deaths and population data in 2020 based on gender, age, and municipality of residence, and we made a comparison with the mortality data in 2017–2019 using a spatially discrete model. Results: Excess mortality was significantly associated with age, gender, and COVID-19 incidence, with larger effects in the second half of 2020. Most municipalities had higher risks of mortality with a number of exceptions in the northeastern part of Belgium. Some discrepancies in excess mortality were observed between the north and south regions. Conclusions: This study offers useful insight into excess mortality and will aid local and regional authorities in monitoring mortality trends. ; Funding T.N. gratefully acknowledges funding by the Internal Funds KU Leuven, Belgium (project number 3M190682) and the Fund for Scientific Research– Flanders, Belgium (grant number G0A4121N). C.F. acknowledges support from the European Union’s Horizon 2020project EpiPose (Grant agreement number 101003688) and European Union’s Horizon Europe– project ESCAPE (Grant agreement number 101095619). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Health and Digital Executive Agency (HADEA). Neither the European Union nor the granting authority can be held responsible for them.