Manning was convicted in 2013 of providing more than 700,000 documents, videos, diplomatic cables and battlefield accounts to WikiLeaks, in the biggest breach of classified materials in US history.
The former intelligence analyst, who was born a man but identifies as a woman, is serving a 35-year sentence at an all-male military prison at Fort Leavenworth, Kansas.
Manning has been charged with a number of disciplinary infractions and will attend a hearing before a three-person discipline adjustment board on Aug. 18 at the prison, attorney Nancy Hollander said.