In the BBC documentary Jared Leto: Hollywood's Dark Secret, 10 women allege Leto behaved in a sexually inappropriate way towards them.
The incidents reported by the BBC are alleged to have taken place between 2002 and 2016, when the actor was in his 30s and 40s. He is now 54.
The women made allegations of sexual assault and statutory rape, as well as the use of explicit and inappropriate language towards teenage girls.
The documentary released on Wednesday also features two accounts from individuals who worked with Leto's band, who both said the staff felt uncomfortable about his conduct.
The BBC says it has seen pictures and messages supporting the women's stories, as well as accounts corroborated by friends and family.
Leto has been a prominent actor since the 1990s, with Fight Club, The Thin Red Line and Girl, Interrupted among his early major film roles.
The star won an Oscar for his role in Dallas Buyers Club, and has also appeared in hit films such as Suicide Squad, Blade Runner 2049 and, most recently, Masters of the Universe.
His award-winning rock band, Thirty Seconds To Mars, was formed in 1998 and is known for tracks such as The Kill, Kings And Queens and This Is War.
The group are touring Europe, and will perform in the UK in 2027.
The Press Association has contacted Leto for comment.
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