Abstract: Compared to the majority population, studies have shown that non-western immigrants are more likely to work in jobs for which they are overqualified. These findings are based on coarse measures of jobs, and an important question is how sensitive these findings are to the definition of jobs. By using detailed information from Norwegian register data 2014, we provide a methodological innovation in comparing individuals working in the same occupation, industry, sector, firm, and municipality. In this way, we measure the degree of overqualification among workers within more than 653,000 jobs. We differentiate between immigrants and their descendants originating from Western Europe, the New EU countries, other Western countries, the Middle East and North Africa (MENA), Africa and Asia (except MENA countries), and South and Central America, and compare their outcomes with the majority population holding the same jobs. We find that immigrants from all country of origin groups are more likely to be overqualified compared to the majority population and to descendants of immigrants. However, the prevalence of overqualification decreases with time since immigration.