The genocide of the Romani people during World War Two occurred throughout Europe and led to the death of approximately 220,000 Romani people, or around 25 per cent of a pre-war population of approximately 1 million.1 The persecution of various Romani groups varied widely throughout the European continent; in some places the UN definition of genocide, including the ‘intent to destroy, in whole or in part’, definitively applied, but in others, the question is more debatable. In understanding the history, motivations, outcomes and horror of the Romani genocide, historians have argued that discussing it in relationship to the Holocaust, while certainly unavoidable, can obscure the specificity of the Romani experience.2 This chapter contends that the Nazis and allied regimes targeted the Romani people in order to destroy them based on their supposed racial heritage, the very definition of genocide. It outlines the history of Romani persecution in Europe, explains debates among historians about the nature and validity of the term genocide, and provides a detailed geographical accounting of the genocide and its victims, perpetrators, bystanders and resisters. At the conclusion, a short Bibliographic Note focused on English sources delineates starting points for both for researchers and students.