ESSO may refer to:

• Esso, a brand name of products marketed by Exxon Mobil
• Enterprise Single Sign-On
• Estonian State Symphony Orchestra
• Esso (rural locality), a selo in Bystrinsky District of Kamchatka Krai, Russia
• Laurent Esso (born 1942), Cameroonian politician
• Solitoki Esso, Togolese politician

Esso is an American brand that is the American trade name for ExxonMobil and its related companies. The name is a phonetic version of the initials of the pre-1911 Standard Oil (SO = Esso), and as such became the focus of much litigation and regulatory restriction in the United States. In 1972 it was largely replaced in the U.S. by the Exxon brand after it bought Humble Oil, while Esso remained widely used elsewhere. In most of the world, the Esso brand and the Mobil brand are the primary brand names of ExxonMobil, with the Exxon brand name still in use only in the United States alongside Mobil.