Not only Swedish studies, but also several international studies, claim an increase in anti-Semitic attitudes in recent decades. As prejudice is acquired in the early years of socialization, and/or is innate and fairly stable over the life cycle, examining adolescents’ attitudes is vitally important. Hence, by controlling for individual demographic and socio-economic background factors, we study two interrelated questions: Has anti-Semitism among Swedish secondary school-age youths changed between 2003 and 2009? Are changes equal across groups, with a specific focus on religious groups? Using two unique cross-section surveys of secondary school-age students in Sweden for the years 2003 and 2009, we try to address the above questions. Our analysis shows, in contrast to the views of the general public and other related studies, that anti-Semitism has decreased slightly during the examined period. Moreover, the study finds a variation in anti-Semitism by religious affiliation: it has increased among Muslim youth, but remains stable in other groups.