This thesis explores the Jewish leadership of the Theresienstadt ghetto in relation to the Czech and German Jewish communities imprisoned there between November 1941 and May 1945. It broadens the category of Jewish leadership by focusing not only on the men who ran the Theresienstadt Judenrat but on the broad spectrum of community leaders, including social, cultural and spiritual leaders. This approach represents a conscious attempt to highlight the relationship between the Jewish elders and their communities, rather than between those elders and the Nazi officials which has characterised much of the previous work on Jewish leadership during the Holocaust. To achieve this shift, this thesis focuses on five main themes. First, the day-to-day work of the leaders in Theresienstadt in the context of their community work prior to the outbreak of the war. Secondly, the conflicts between the German and Czech communities in the ghetto. Thirdly, the conflict between the assimilationist and the Zionist factions in the ghetto, both within and across national groups. Fourthly, the existence of education and welfare programmes as survival mechanisms in the lives of the young, and finally, the existence and importance of a cultural and spiritual life for the ghetto inhabitants. This thesis uses a wide range of historical sources, focusing primarily on the diaries, memoirs, and oral testimonies of those who were imprisoned in the ghetto. It is only by including their accounts that we can begin to understand how the ghetto was interpreted by the Jewish leaders and experienced by the broad mass of Czech and German Jewry.