The singer, 22, who has spoken openly about her sexuality in the past, revealed to Paper magazine her mom's reaction to the news.
"I remember telling her I admire women in a different way," Cyrus told the magazine. "And she asked me what that meant. And I said, I love them. I love them like I love boys. And it was so hard for her to understand.
"She didn't want me to be judged and she didn't want me to go to hell. But she believes in me more than she believes in any god. I just asked for her to accept me. And she has."
Cyrus said she has long had romantic feelings for both women and men.
"I am literally open to every single thing that is consenting and doesn't involve an animal and everyone is of age," Cyrus said. "Everything that's legal, I'm down with. Yo, I'm down with any adult — anyone over the age of 18 who is down to love me. I don't relate to being boy or girl, and I don't have to have my partner relate to boy or girl."
"As long as you're not hurting anyone," she continued. "Your choices are your choices."
Cyrus appears on the cover of Paper magazine's "Use Your Voice" issue, which goes on stands June 22.