ABSTRACT Educational success is central to the life chances of young people, but increasing differences in student achievement between schools are commonly attributed to increasing school segregation. The aim of the study was to examine the trends in socioeconomic, ethnic, and academic segregation in compulsory and upper secondary education in the Gothenburg school market between 1998 and 2020. Utilizing register data from the Gothenburg Longitudinal Database (n = 1 662 166), the study showed that school segregation intensified over time and across education levels, particularly in the Gothenburg municipality and upper secondary education. The geography of upper secondary education becomes more clustered after stricter upper secondary qualifications are implemented. These findings are discussed in relation to the Swedish school reforms that resulted in the materialization and expansion of the school market with a significant increase in school provisions, leading to the (re-)production of unjust geographies.