Not only in Sweden, but also in several international studies, it has been shown that a non-negligible proportion of the European population subscribes to classical anti-Semitic notions, and that anti-Semitism is a phenomenon that is still very much present in post-1945 Europe, more so in some countries than others. Moreover, there is evidence of an increase in anti-Semitic attitudes and incidents in recent decades. The latter is also depicted as being related to the Israeli-Palestinian conflict, especially the Israeli military operation Cast Lead of 2008-2009 which resulted in Jews being blamed for the political and military actions of the State of Israel. 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 because they can help us to understand what might happen in the future. Hence, the aim of this study is to study three interrelated questions: Which factors explain anti-Semitism among secondary school youths in Sweden? Is religious affiliation an important factor in explaining anti-Semitism among Swedish youth? Has anti-Semitism among Swedish secondary school youths increased between 2003 and 2009? Using two unique surveys of secondary school students in Sweden for the years 2003 and 2009, we try to address the above questions. The results of our analysis show that in general anti-Semitism amongst Swedish youths is in line with the results of earlier studies. However, in contrast to the views of the general public, it has not increased during the examined period but has instead decreased. Moreover, we show that anti-Semitism has increased amongst Muslim youth.