Sir Hubert Miles Gladwyn Jebb, First Lord and Baron Gladwyn, known as Gladwyn Jebb (April 25, 1900 - October 24, 1996), was a prominent British civil servant, diplomat and politician.

The son of Sydney Jebb, of Firbeck Hall, Yorkshire, Jebb was educated at Eton College, then Magdalen College, Oxford, gainint a first in History. In 1929 he married Cynthia, with whom he had one son and two daughters.

Jebb entered the Diplomatic Service in 1924 and served in Tehran, Rome and the Foreign Office. After World War II, he served as the first Acting United Nations Secretary-General 1945-1946, then became the United Kingdom's Ambassador to the United Nations 1950-1954 and to Paris 1954-1960.

In 1960 Jebb was made a hereditary peer as Baron Gladwyn and became involved in Liberal Party politics. He was Deputy Leader of the Party 1965-1988, spokesman on foreign affairs and defence. He served as a Member of the European Parliament 1973-1976 and contested the Suffolk seat in the European Parliament in 1979.

Jebb's wife, Cynthia, was a diarist of their times in Paris and in Liberal politics.