John Frederic Gretton, 2nd Baron Gretton OBE (15 August 1902 – 26 March 1982), was a British peer and Conservative Member of Parliament.
Gretton was the son of John Gretton, 1st Baron Gretton, and Hon. Maud Helen de Moleyns, daughter of Dayrolles Blakeney Eveleigh-de-Moleyns, 4th Baron Ventry. Lord Gretton was educated at Eton.
He was elected to the House of Commons for Burton in 1943 (succeeding his father), a seat he held until 1945. Two years later he succeeded his father as second Baron Gretton and entered the House of Lords.
Lord Gretton married on 6 May 1930 Anna Helena, known as Margaret, elder daughter of Captain Henrik Loeffler, of 51 Grosvenor Square, London. She was a JP in 1943 for Staffordshire and lived at the Rectory, Ufford, near Stamford, Lincolnshire.