Casey Affleck Bails on The Oscars, Won't Present Best Actress Award

Casey Affleck is backing out of presenting at the upcoming Academy Awards ... TMZ has learned.

The Academy tells us ... Affleck notified them he won't be presenting the Best Actress award at the Oscars on March 4, which is traditionally always presented by the Best Actor winner from the previous year.

According to our sources ... Casey has a lot of respect for the Oscars, and doesn't want the Best Actress category to be about him presenting. We're told he wants the attention to be focused on the nominees ... and doesn't want his presence to impact the winner's special moment.

As you'll recall ... Casey won at the 2017 Oscars for his role in "Manchester by the Sea," despite controversy surrounding past allegations of sexual harassment against him.