Major John Seymour Chaloner (5 November 1924 – 9 February 2007) was a British journalist, author and military officer who co-founded the German newsweekly Der Spiegel.
During the Second World War, he enlisted in the British Army and in 1945 became a member of the Westminster Dragoons at the rank of major.
At the end of the war, Chaloner was assigned to the Public Relations and Information Services Control (PRISC), a unit that was to rebuild press, theatre, radio and cinema in Germany on behalf of the Foreign and Commonwealth Office, While supervising the press in Hanover, he joined forces with two other British officers, Czech emigrant Harry Bohrer and German Emigrant Henry Ormond to build a political weekly magazine modelled after Time magazine.
The magazine was published in 1946 under the title Diese Woche (This Week) with Bohrer as acting editor-in-chief.
Chaloner then worked initially in the public relations of Field Marshal Bernard Montgomery.