Dag Ramsøy Bryn (17 March 1909 – 11 April 1991) was a Norwegian diplomat and politician for the Labour Party.
He was the son of Zakarias Bryn (1880-1943) and Ragna Emilie Canelius (1883-1949).
During World War II, he left Norway aboard the M/B Haugen arriving at Lerwick in 1941.
After the liberation of Norway during 1945, he played a role in the design of Norwegian foreign and security policy.
After this, he served as Norwegian ambassador to various foreign capitals including Bonn (1954 to 1957) and Belgrade (1958-1963).