Aja (, pronounced "Asia") is the sixth studio album by the American jazz rock band Steely Dan, released by ABC Records on September 23, 1977. On the album, band leaders Donald Fagen and Walter Becker pushed Steely Dan further into experimenting with different combinations of session players, enlisting the services of nearly 40 musicians, while pursuing longer, more sophisticated compositions and arrangements.

The album peaked at number three on the Billboard Top LPs & Tape chart, and number five on the UK Albums Chart, ultimately becoming Steely Dan's most commercially successful release. It spawned the hit singles "Peg", "Deacon Blues", and "Josie".

At the 20th Annual Grammy Awards, Aja won Best Engineered Recording – Non-Classical, and was nominated for Album of the Year and Best Pop Performance by a Duo or Group with Vocals. It has appeared on many retrospective "greatest albums" lists, with critics and audiophiles applauding the album's high production standards. In 2010, the album was recognized by the Library of Congress as being "culturally, historically, or aesthetically significant" and selected for preservation in the National Recording Registry.