John Hall-Stevenson (1718–1785), in his youth known as John Hall, was an English country gentleman and writer.
He is memorialised as 'Eugenius' in Laurence Sterne's novels Tristram Shandy and A Sentimental Journey Through France and Italy.
Hall-Stevenson was the son of Joseph Hall of Durham by his marriage to Catherine, sister and heiress of Lawson Trotter of Skelton Castle at Skelton-in-Cleveland, Yorkshire.
On 16 June 1735, at the age of seventeen, he matriculated at Jesus College, Cambridge as a fellow-commoner. He quickly struck up a close and lifelong friendship with Laurence Sterne, who was five years older. They referred to each other as cousins, but no kinship is known. Hall was precociously ribald and loved Rabelaisian literature. He left Cambridge without a degree in about 1738 and made the grand tour.
On his return to England at the age of twenty, Hall married Anne, the daughter of Ambrose Stevenson of the Manor House, Durham, and added his wife's surname to his own. After the Jacobite Rising of 1745, his uncle Lawson Trotter, a supporter of Jacobitism, fled overseas, and the fifteenth-century Skelton Castle came into the possession of Hall-Stevenson's mother. On her death, he inherited it, by then half-ruined
Hall-Stevenson had no love of field sports and spent his time on literature and entertaining his friends. He wrote verse in imitation of La Fontaine and collected kindred spirits which whom he formed a "club of demoniacks" which met at Skelton several times a year. The club indulged in heavy drinking and orgies which were pale reflections of those of Francis Dashwood and his friends at Medmenham. The "demoniacks" included the clergyman Robert Lascelles, nicknamed Pantagruel, Zachary Moore, Colonel Hall, Colonel Lee, and Andrew Irvine of Kirkleatham. On his visits to London, Hall-Stevenson met John Wilkes and Horace Walpole, and three familiar letters from him to Wilkes written in 1762 survive. He also claimed a friendship with Rousseau.