Isaac John Fowler (27 August 1894 – 17 June 1981) was a Welsh dual-code international rugby union, and professional rugby league footballer who played in the 1910s and 1920s. He played representative level rugby union (RU) for Wales, and at club level for Ammanford RFC and Llanelli RFC, as a scrum-half, and representative level rugby league (RL) for Wales, and the Other Nationalities, and at club level for Batley (vice-captain), as a scrum-half.