Scott, 78, who has yet to win an Oscar over a career spanning six decades, is nominated for space adventure «The Martian,» about an astronaut stranded on Mars.
Iñárritu was named best drama director at the Golden Globes on Sunday while Scott won best comedy/musical film director.
Also nominated by the DGA on Thursday was director Tom McCarthy for «Spotlight,» about the Boston Globe’s probe into the Catholic Church’s cover-up of child molestation; Adam McKay for comedy «The Big Short,» exploring the 2007 U.S. financial collapse, and Australian director George Miller for gritty action film «Mad Max: Fury Road.»
The DGA nominations, voted for by a group of Hollywood directors, many of whom are also Oscar voters, come ahead of Thursday’s Academy Award nominations.
Since 1948, only seven winners of the DGA prize have failed to go on to win the best director Oscar.
The directors of «Carol,» «Bridge of Spies» and «Creed,» were among those failing to make the DGA’s list this time.
The DGA also nominated five filmmakers for directing a first-time feature film in 2015, including actor Joel Edgerton, who turned director for thriller «The Gift.»
The category also includes British filmmaker Alex Garland for sci-fi thriller «Ex Machina,» Hungarian director Laszlo Nemes for «Son of Saul,» Brazilian newcomer Fernando Coimbra for «A Wolf at the Door,» and Marielle Heller for coming-of-age tale «The Diary of a Teenage Girl.»
Despite a recent backlash against the lack of diversity both on and off screen in Hollywood, Heller was the only woman to be nominated in either category.