Sir John Evelyn Leslie Wrench KCMG (29 October 1882 – 11 November 1966) was a British author and journalist who was editor of The Spectator.

He was the founder of the Royal Over-Seas League (ROSL) and the English-Speaking Union (ESU), both established to foster international communication and education.

At the age of five years, his favourite literature was Army and Navy Stores catalogues, which his parents gave him to keep him quiet during railway journeys.

Wrench, however, was less interested in success in journalism than in his visions of Commonwealth development awakened by his visits to Canada and the United States.

He told in his book Uphill, the first volume of his autobiography, how in 1910 a turning point came in his life, crystallizing itself in his memory as a "vision" that came to him at the memorial service to King Edward VII in Westminster Abbey, where he said, "the scales fell from my eyes, I vowed I would devote my life to great causes – to the Empire, to my fellows."

Passionately longing to make a more personal contribution to the unity of the British Empire, he formed in 1910 The Royal Over-Seas League as The Overseas Club in order to encourage international understanding.

In 1911, while in New Zealand, he gave Captain Robert Falcon Scott, R.N., the British Antarctic explorer, a clean handkerchief immediately before the latter's departure for the South Pole.

His club made rapid progress and during the war of 1914–1918 its contribution included the Empire Fund to provide tobacco for the forces.

He reached the rank of major and served as principal private secretary to Lord Rothermere when he was President of the Air Council, and later as his deputy when controller for the dominions and United States at the Ministry of Information.

As a result of his experience in this last appointment, Wrench founded in 1918 the English-Speaking Union of the Commonwealth "in no narrow attitude of race pride, in no spirit of hostility to any people" and created the mission statement of the English-Speaking Union in the first edition of the organization's magazine, Landmark: "Believing that the peace of the world and the progress of mankind can be largely helped by the unity in purpose of the English-Speaking Democracies, we pledge ourselves to promote by every means in our power a good understanding between the peoples of the USA and the British Commonwealth."

Its special field in attempting understanding between the English and German peoples was poorly nurtured in the hostile soil of increasing Nazism.

She was the daughter of Sir Victor Brooke, Bt., sister of Field Marshal Lord Alanbrooke, and widow of Frederick Henry Arthur des Vouex.

He described broadcasting as the future ‘University of the whole Nation.’ In 1958, he founded and served as chairman of the Commonwealth Union of Trade "to strengthen the economic bonds" among member countries.

Another result of his latter enthusiasms was the foundation in 1958 of the Anglo-Kin Society with the aim of encouraging literary, historical, and topographical research to provide fuller information about places and events in Britain likely to be of interest to the British Commonwealth and the United States.

From 1961 to 1964, he was President of the Dickens Fellowship; and for many years he was senior trustee of the Cecil Rhodes Memorial Museum Foundation in Bishop's Stortford, England.

His hobbies included studying social problems, trying to learn languages, comparing notes with people of other nations, walking, motoring, and sunbathing.

W. V. Griffin wrote a book about him, Sir Evelyn Wrench and his continuing vision of international relations during 40 years (New York: 1950).