The 2013 nominees will be unveiled on 10 January – five days earlier than normal and three days ahead of the Golden Globes.
The Academy of Motion Picture Arts and Sciences (AMPAS) said it would “provide members and the public a longer period of time to see the nominated films”.
The 85th Academy Awards will be held in Hollywood on 24 February.
In recent years the Golden Globe Awards, hosted by the Hollywood Foreign Press Association (HFPA), have preceded the Oscar nominations announcement.
According to industry website Deadline Hollywood, bringing the latter forward could “blunt the impact” of the HFPA event.
“The Academy’s nomination announcement will get enormous attention just as the Hollywood Foreign Press Association is drumming up attention for its own big night,” wrote columnist Pete Hammond.
In The Hollywood Reporter, Scott Feinberg suggested the Academy’s board of governors hoped “to grab back some of the thunder that has been stolen in recent years by the ever-increasing number of awards shows”.
The changes, he said, “could have a major impact on awards season and on the viewing experiences of the Academy’s own members”.
As part of the Oscars shake-up, many of the Academy’s 6,000 members will also have the opportunity to vote online for the first time.
From 17 December a new system will allow them to vote on their preferred films, actors and technical film achievements by email.
The Directors Guild of America (DGA) had planned to announce its award nominations on 10 January but will now do so two days earlier.