John O'Hanlon (23 April 1876, Portadown - 20 February 1960, Dublin) was an Irish chess master.
He won nine times Irish Chess Championship, first title in 1913 and the last in 1940. He also played in British championships (among others, he tied for 8th/9th at Oxford in 1910 and 7th-9th at Stratford-upon-Avon in 1925, both won by Henry Ernest Atkins).
In other tournaments, he shared 1st with Max Euwe at Broadstairs in 1921, took 8th at the Hastings International Chess Congress in 1921/22 (Boris Kostić won), tied for 1st-3rd with Marcel Duchamp and Vitaly Halberstadt at Hyères in 1928, and took 12th at Nice 1930 (Savielly Tartakower won).
The O'Hanlon Cup in the fourth division of the Leinster Chess Union is named in his honour. In the 1960s a group of visually impaired chess players formed the O'Hanlon Chess Club in Dublin, they competed in the Leinster Leagues, winning the O'Hanlon Cup, and progressing through the leagues, until 1967 when they disbanded.