Domingo Cullen (1791 – 21 June 1839) was the governor of province of Santa Fe, Argentina during 1838.
Cullen was born in Tenerife, Canary Islands, but moved to Argentina in the 1820s after establishing commercial activities (linked with fluvial trade) in the area. He met Santa Fe's caudillo Estanislao López when serving as a deputy of the Cabildo of Montevideo. After being involved in activism related to the independence of Uruguay and the resistance against Brazil (see Cisplatine War), he returned to Santa Fe, settled in a ranch, and married Joaquina Rodríguez del Fresno, the young widow of Pedro Aldao and sister-in-law of López. In 1828 he became a counselor of López, and his Minister of Government in 1833.
At the time of López's death on 15 June 1838, Cullen was in Buenos Aires as representative of Santa Fe, trying to find a peaceful solution to the ongoing French blockade of the port (caused by a law of 1821 that obligated resident foreign citizens of the province of Buenos Aires to serve in conscription). Cullen argued that the blockade was the result of a provincial law and therefore the other provinces were not bound to help Buenos Aires. Juan Manuel de Rosas, the powerful governor of Buenos Aires, contended that this violated the Federal Pact.
When Cullen returned to Santa Fe, he became governor, but his election was not acknowledged by Rosas and by Pascual Echagüe, governor of the neighbouring Entre Ríos Province. Without López's support, he faced opposition from his personal enemies in the province and from those loyals to Rosas. In the end, all provinces including Santa Fe ended up supporting Buenos Aires against the French, and Cullen was forced to resign and go to exile.