Teodoro "Theo" Rafael Arguelles Yangco (November 9, 1861 – April 20, 1939) was a Filipino businessman who served in a variety of public and civic offices, and was considered to be the foremost Filipino philanthropist of his time. He served as the Resident Commissioner of the Philippines (1917–1920). He was the longest serving president of the YMCA in the Philippines (1911–1925) and was called the "Father of the YMCA of the Philippines".