Akhnaten is an opera in three acts based on the life and religious convictions of the Egyptian pharaoh Akhenaten (Amenhotep IV), written by the American composer Philip Glass in 1983. The libretto is by Philip Glass in association with Shalom Goldman, Robert Israel, Richard Riddell and Jerome Robbins. Akhnaten was commissioned by Württembergische Staatstheater, Stuttgart and had its world premiere on March 24, 1984, at the Stuttgart State Theatre, under the German title Echnaton. Paul Esswood sang the title role, German director Achim Freyer staged the opera in an abstract style with highly ritualistic movements. The American premiere, directed by David Freeman, was on October 12, 1984, at the Houston Grand Opera, where Glass's opera The Making of the Representative for Planet 8 also premiered. The UK premiere, based on the American production, was on June 17, 1985 by English National Opera at the London Coliseum. This production was revived at the London Coliseum in March 1987. The award-winning Polish premiere, directed by Henryk Baranowski, was on May 20, 2000 at the Grand Theatre in Łódź. A new co-production by English National Opera and LA Opera and in collaboration with Improbable directed by Phelim McDermott starring Anthony Roth Costanzo and Zachary James premiered at the London Coliseum on March 4, 2016, which won a 2017 Olivier Award, and at LA Opera on November 5, 2016. A revival of this production in London took place in March 2019 and played at the Metropolitan Opera in their 2019/2020 season. A new production directed by Laura Scozzi premiered at the Theater Bonn, Germany on March 11, 2018.

According to the composer, this work is the culmination of his two other biographical operas, Einstein on the Beach (about Albert Einstein) and Satyagraha (about Mahatma Gandhi). These three people – Akhenaten, Einstein and Gandhi – were all driven by an inner vision which altered the age in which they lived, in particular Akhenaten in religion, Einstein in science, and Gandhi in politics.

The text, taken from original sources, is sung in the original languages, linked together with the commentary of a narrator in a modern language, such as English or German. Egyptian texts of the period are taken from a poem of Akhenaten himself, from the Book of the Dead, and from extracts of decrees and letters from the Amarna period, the seventeen-year period of Akhenaten's rule. Other portions are in Akkadian and Biblical Hebrew. Akhnaten's Hymn to the Sun is sung in the language of the audience.