There Will Be Blood is a 2007 American drama film written, co-produced, and directed by Paul Thomas Anderson.

Writer-director Paul Thomas Anderson steps outside his contemporary world of dysfunctional Angelenos to explore a very different dysfunctional man—an oil pioneer whose trailblazing spirit is equaled only by his murderous ambition. There Will Be Blood is Anderson's loose adaptation of the novel Oil! by Upton Sinclair, and it focuses its attentions on Daniel Plainview (Daniel Day-Lewis), a miner who happens upon black gold during a disastrous excavation that ends in a broken leg. Pulling himself up from the bowels of the earth, both literally and metaphorically, Plainview embarks on a systematic and steadfast approach to mastering the oil business. Using plain-spoken and straightforward language, Plainview launches a campaign to convince small-town property owners they should let him drill their land. Without him, they won't have the equipment to access the profit beneath their feet. He builds an empire this way -- and gradually becomes obsessed with the intrinsic value of power, growing increasingly irascible and paranoid in the process. Plainview meets his match in Eli Sunday (Paul Dano), a teenage preacher in the small California town of Little Boston, whose brother tipped Plainview off to the town's plentiful supply of untapped oil. To fully reap the benefits of the land, Plainview must suffer the opposing whims of this "prophet", whose legitimacy is questionable at best. And it's unclear if either man is prepared to pay the humiliating price the other wants to exact. There Will Be Blood features an anachronistic soundtrack by Radiohead's Jonny Greenwood, and it was shot in the same town where the James Dean epic Giant was filmed.

The film received significant critical praise and numerous award nominations and victories. It appeared on many critics' "top ten" lists for the year, notably the American Film Institute, the National Society of Film Critics, the National Board of Review, and the Los Angeles Film Critics Association. Day-Lewis won Oscar, BAFTA, Golden Globe, Screen Actors Guild, NYFCC and IFTA Best Actor awards for his performance. The film was nominated for eight Academy Awards including Best Picture, winning Best Actor for Day-Lewis and Best Cinematography for Robert Elswit.

In late 2009, it was chosen by Lisa Schwarzbaum of Entertainment Weekly, Peter Bradshaw of The Guardian, Peter Travers of Rolling Stone and Michael Phillips of the Chicago Tribune and At the Movies as the best film of the first decade of the 21st century.