ExxonMobil's Baytown Refinery is a major oil refinery named after and located in Baytown, Texas. It has capacity of 588,000 barrels per day (93,500 m/d). The site first opened in 1919 and was originally operated by the Humble Oil Company. Today, it is the largest employer in the city. The plant takes up 2,400 acres (9.7 km) of land next to the Houston Ship Channel.

The Baytown Refinery is the fifth-largest refinery in the United States by production, after the nearby Port Arthur Refinery. Baytown is also ExxonMobil's third largest refinery, only trailing Exxon's Beaumont Refinery and Jurong Island refinery in Singapore.

On December 23, 2021, a large explosion occurred at the refinery in what was described as a major industrial accident by both local and national news. The explosion, caused by a fire, occurred around 1AM and seriously injured five workers, four of whom were airlifted to the hospital with one being transported by ambulance. No fatalities were reported. Two of the injured contract workers have filed a $10 million lawsuit against ExxonMobil and partner Team Industrial Services for unsafe working conditions as of a result of the explosion.