The singer, who officially turned 21 on Saturday, waited until Sunday to celebrate following her appearance at the American Music Awards in Los Angeles.
Cyrus closed out the show with a bizarre performance of her hit song “Wrecking Ball,” which featured a video of a pussycat lipsynching her song in the background.
Following the AMAs, she and some friends including One Direction star Niall Horan, Kelly Osbourne, Tyler, The Creator and Wiz Khalifa partied at Hollywood hangout Beacher’s Madhouse at the Roosevelt Hotel.
Videos and photos posted online show strippers entertaining partygoers and the venue covered with inflatable dolls and gigantic, life-size photos of the pop star.
A person dressed as Dr. Seuss character The Lorax entertained guests, who were given cut-out masks of Cyrus to wear during the party.