Theodorus "Theo" van Gogh (1 May 1857 – 25 January 1891) was a Dutch art dealer. He was the younger brother of Vincent van Gogh, and Theo's unfailing financial support allowed his brother to devote himself entirely to painting. Theo died at the age of 33, several months after Vincent had died at the age of 37.
Theodorus "Theo" van Gogh was born on 1 May 1857 in the village Groot-Zundert in the province of Brabant, Netherlands. He was the son of Theodorus van Gogh and Anna Cornelia Carbentus. His elder brother was Vincent van Gogh (1853–1890), who later became a famous painter.
Vincent worked for some years at the Dutch (The Hague) office of the Parisian art dealers Goupil & Cie, and Theo joined the Brussels office on 1 January 1873 as their youngest employee. After Vincent was transferred to the London office, Theo moved to the office in The Hague, where he developed into a successful art dealer. By 1884, he was transferred to the Paris main office. Starting in the winter of 1880–1881, he sent painting materials as well as monthly financial support to Vincent, who was living back in the Netherlands.