Sir John Anthony Cecil Tilley, GCMG, GCVO, CB, PC (January 1869 – 5 April 1952) was a British diplomat. He was British Ambassador to Brazil from 1921 to 1925, and Ambassador to Japan from 1926 to 1931.
Born on 21 or 31 January 1869, Tilley was the ninth child and fourth son of Sir John Tilley, Secretary to the General Post Office, by his third marriage, to Susannah Anderson Montgomerie. She was the grand daughter of Alexander Montgomerie; daughter of William Eglinton Montgomerie of Annick Lodge and Greenville, Ayrshire by his marriage to Susanna Fraser Anderson and great niece of Hugh Montgomerie, 12th Earl of Eglinton. Tilley was the half brother of Arthur Augustus Tilley. and godson of Anthony Trollope.
Before being awarded a scholarship to Eton, Tilley attended a preparatory school at Thorpe Mandeville, Northamptonshire, and on 8 October 1887 entered King's College, Cambridge, where he graduated BA in 1890, proceeding MA in 1894. Between 1887 and 1889 he was editor of the Cambridge Review, an undergraduate magazine. He then prepared for the Foreign Office entrance examination. To improve his "moderately good" French he spent three months in a village near Tours, France. He then moved to live with a family in Dresden, Germany, to learn German, where he also learnt some Spanish. From Dresden, he returned to England and attended Scoones where he crammed for the Foreign Office entrance examination