Robert Ritter (14 May 1901 – 15 April 1951) was a German racial scientist doctor of psychology and medicine, with a background in child psychiatry and the biology of criminality. In 1936, Ritter was appointed head of the Racial Hygiene and Demographic Biology Research Unit of Nazi Germany's Criminal Police, to establish the genealogical histories of the German "Gypsies", both Roma and Sinti, and became the "architect of the experiments Roma and Sinti were subjected to." His pseudo-scientific "research" in classifying these populations of Germany aided the Nazi government in their systematic persecution toward a goal of "racial purity".