The association reportedly made the announcement Wednesday, following a trend for the DC universe's theatrical films, including Batman V. Superman, which also earned a PG-13 rating.
Bowing in theaters Aug. 5, Suicide Squad's at times disturbing, suggestive storyline and characters, including the murderous Joker, had some early reports predicting an R-rating, especially after Marvel's Deadpool broke ground by becoming the first R-rated superhero film.
But last year, Squad producer Charles Roven told Collider he didn't expect an R, saying a PG-13 rating would be consistent with other DC films. It would be "right there on the edge of PG-13, but still PG-13," he said at the time.
Some of the cast completed unexpected acts to prepare themselves and their fellow castmates for the dark anti-hero flick. Leto, 43, for example sent gross gifts to his colleagues including a live rat, used condoms and at one point, a dead pig carcass.
Supermodel Cara Delevingne, who plays the sorceress Enchantress, prepped for her role with a walk in the woods sans clothing. She said director David Ayer encouraged her to "try and find a forest and, if it was a full moon, get naked and walk in the woods with my feet in the mud, which I did. There wasn't a full moon, but I howled like a wolf."