Petróleos Mexicanos or Pemex (Spanish pronunciation: [ˈpemeks], Mexican Petroleum) is a Mexican state-owned petroleum company. Pemex has a total asset worth of $415.75 billion, and is the world's second largest non-publicly listed company by total market value, and Latin America's second largest enterprise by annual revenue as of 2009. However, the majority of its shares are non-publicly listed and under control of the Mexican government. The value of its publicly listed shares totalled $102 billion in 2010, representing approximately one quarter of the company's total worth.

Asphalt and pitch had been worked in Mexico since the time of the Aztecs. Small quantities of oil were first refined into kerosene around 1876 near Tampico. By 1917 commercial quantities of oil were being extracted and refined by subsidiaries of the British Pearson and American Doheny companies, and had attracted the attention of the Mexican government who then claimed all mineral rights for the state as part of its Constitution.