Paul Gruda Koht (7 December 1913 – 26 March 2002) was a Norwegian diplomat.
He was born in Bærum as a son of Halvdan Koht (1873–1965) and Karen Grude Koht 1871–1960. He was a brother of Åse Gruda Skard. He was a grandson of Paul Steenstrup Koht and Martin Adolf Grude, and through his sister he was a brother-in-law of Sigmund Skard and uncle of Halvdan Skard, Målfrid Grude Flekkøy and Torild Skard.
In January 1938 he married architect Grete Sverdrup (1913–1996).
He finished his secondary education at Stabekk in 1932, and graduated from the University of Oslo (Royal Frederick University) in 1938 with the cand.jur. degree. He also studied briefly at the London School of Economics and in Paris. In 1938 he was hired as a secretary in the Ministry of Foreign Affairs, which was headed by his father. He was stationed at the Norwegian legation in Bucureşti for some time, but left in November 1939. Following the German attack on Norway in April 1940 he briefly served as liaison for French forces fighting at Narvik, before serving as a diplomat in London, Tokyo and New York City. His father resigned at Minister of Foreign Affairs in November 1940.