Ragnar Arthur Granit (October 30, 1900, Riihimäki, Finland – March 12, 1991, Stockholm, Sweden) was a Finnish / Swedish scientist who was awarded the Nobel Prize in Physiology or Medicine in 1967 along with Haldan Keffer Hartline and George Wald.

Granit graduated in 1927 from the Faculty of Medicine of the University of Helsinki, Finland. When Finland became the target of a massive Soviet attack in 1940 during the Winter War (1939 - 1940), Granit sought refuge - and peaceful surroundings for his studies and research work - in the neighbouring capital of Sweden, Stockholm, at the age of 40.

In the same year, 1940, Granit also received Swedish citizenship, which made it possible for him to go on with his work and live without having to worry about the war, which lasted until 1945 in Finland. Granit kept his Finnish citizenship as well, and he remained a patriotic Finn throughout his life. After the Finnish - Russian Wars, Granit kept homes both in Finland and Sweden.

Granit was professor of neurophysiology at the Karolinska Institutet from 1946 to his retirement in 1967.

Granit said that his Nobel prize "belongs fifty - fifty to Finland and Sweden".