This working paper is D7.3 (T5.1) of the Horizon Europe project 'Global Strategy for Skills, Migration and Development' (GS4S). The paper explores the overeducation of tertiary-educated migrants in European labour markets. Using data from the European Labour Force Survey (2012–2022), we show that immigrants, particularly those from non-EU countries, are significantly more likely to be overeducated than natives. Despite a general decline in overeducation levels for all groups over time, the immigrant-native gap remains, especially for foreign-educated migrants. Furthermore, the likelihood of overeducation for foreign-educated migrants increases until 15–19 years after migration, a pattern consistent across all areas of origin and migration cohorts. Importantly, differences in educational quality between origin and destination countries do not primarily account for these overeducation differentials. The findings underscore the need for policies that better align immigrants’ skills with labour market demands in Europe to avoid the waste of valuable immigrants’ skills, which are harmful not only to migrants but to the economies of receiving countries too.