Johan Thorsten Sellin (26 October 1896 – 17 September 1994) was a Swedish American sociologist at the University of Pennsylvania, a penologist and one of the pioneers of scientific criminology.
Sellin was born in Örnsköldsvik in Västernorrland County, Sweden and came to Canada with his parents when he was 17 years old. He received his bachelor's degree from Augustana College in Illinois when he was 19. He went on to receive a master's degree and doctoral degree in sociology from the University of Pennsylvania.
He taught at the University of Pennsylvania from 1922 until he retired in 1967. Dr. Sellin came to prominence in the 1920s and 30s for his studies in the use of criminal statistics at local, state, national and international levels. He later helped draft the U.S. Uniform Criminal Statistics Act in 1944.
An expert on crime statistics, he advised the Federal Bureau of Investigation about statistical matters and was a consultant to the Bureau of the Census on criminal statistics. He also headed, or was a member of, various United Nations panels of experts on criminological questions. Dr. Sellin was a visiting professor or lecturer at Princeton, the University of California at Berkeley, Oxford and other universities.
Active in international groups, he was secretary-general of the Bern-based International Penal and Penitentiary Commission (later called the International Penal and Penitentiary Foundation) from 1949 to 1951. He was president of the International Society of Criminology from 1956 to 1965. Sellin edited the Annals of the American Academy of Political and Social Science for 39 years, from 1929 to 1968.