BACKGROUND: Indonesia has the second highest smoking prevalence among adult males in the world, with over 61.4 million current smokers. However, there is no national regulation on outdoor tobacco advertising.OBJECTIVE: >To assess the density of outdoor tobacco advertising around schools in Semarang City, Indonesia.METHODS: We conducted geospatial analyses using buffer and hotspot analyses based on advertising and school data in ArcMap 10.6. We statistically tested the significance of different densities, including between 100 m and 100-300-m buffers from schools using Stata 15.1.RESULTS: We found a total of 3453 tobacco advertisements, of which 3026 (87%) were at least medium in size (1.3 m x l.9 m), and 2556 (74%) were within 300 m of schools. We also found hotspots with a 45% higher density of adverts within 100 m of schools (compared to within 100-300 m). A total of 378 schools (39%) were in these advertising hotspots.CONCLUSION: There was high density of outdoor tobacco advertising, with significant clusters in close proximity to schools in Semarang City. The policy implications of this are discussed.