Unocal Corporation
| Industry | Petroleum | 
|---|---|
| Founded | October 17, 1890 | 
| Founders | |
| Defunct | August 11, 2005 | 
| Fate | Acquired by Chevron | 
| Headquarters | Union Oil Center, | 
| Brands | 76 (1932–97) | 
| Number of employees | 6,400 (2005) | 
| Website | unocal.com (defunct) | 
Union Oil Company of California, and its holding company Unocal Corporation, together known as Unocal /ˈjuːnoʊkæl/ was a major petroleum explorer and marketer in the late 19th century, through the 20th century, and into the early 21st century. It was headquartered in El Segundo, California, United States.
Unocal was involved in domestic and global energy projects. Unocal was one of the key players in the CentGas consortium, which attempted to build the Trans-Afghanistan Pipeline to run from the Caspian area, through Afghanistan, to the Indian Ocean, at a time after the Taliban siege of Kabul in 1996.
On August 10, 2005, Unocal merged its entire upstream petroleum business with Chevron and became a wholly-owned subsidiary. Unocal then ceased operations as an independent company, but continues to conduct many operations as Union Oil Company of California, a Chevron company.