The 93rd Academy Awards will now take place on April 25 2021, the Academy of Motion Picture Arts and Sciences.
Next year's ceremony was originally scheduled for February 28.
The opening of the Academy Museum of Motion Pictures has also been pushed back, from December 14 to April 30 2020 the body said.
The Academy has also announced the eligibility period for Oscars consideration has been extended beyond the standard December 31 deadline.
This is the fourth time the Oscars have been postponed.
The 10th Academy Awards were delayed due to the Los Angeles flood of 1938.
The 1968 ceremony was pushed back by two days following the assassination of Martin Luther King Jr and in 1981 the Oscars were delayed by a day following an assassination attempt on president Ronald Reagan.
A feature film must now have a qualifying release date between January 1 2020 and February 28 2021, the Academy said.
The submission deadline for speciality categories – animated feature film, documentary feature, documentary short subject, international feature film, animated short film and live action short film – is December 1 2020.
The submission deadline for general entry categories, including best picture, original score and original song, is now January 15 2021, organisers said.
The postponement of the Oscars raises the prospect of the other major awards shows, including Golden Globes and Screen Actors Guild Awards, following suit.