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.
He died in March 1982, aged 79, and was succeeded in the barony by his son John Henrik Gretton.