Oil! is a novel by Upton Sinclair, first published in 1926–27 and told as a third-person narrative, with only the opening pages written in the first person. The book was written in the context of the Harding administration's Teapot Dome Scandal and takes place in Southern California. It is a social and political satire skewering the human foibles of all its characters.

Upton Beall Sinclair Jr. was an American writer, muckraker, political activist and the 1934 Democratic Party nominee for governor of California. He wrote nearly 100 books and other works in several genres. Sinclair's work was well known and popular in the first half of the 20th century, and he won the Pulitzer Prize for Fiction in 1943.