The bodies of John Paul Bennett, 13, Lacey Bennett, 11, their mother Terri Harris, 35, and Lacey’s friend Connie Gent, 11, were discovered at a property in Chandos Crescent in Killamarsh, near Sheffield, on Sunday morning.
Derbyshire Police said Damien Bendall has been charged with their murder and remains in custody.
The force said the four bodies were found after police responded to a call about concerns for the safety of a man at the address at 7.26am.
Police had previously said officers did not have any prior contact with those involved.
Bendall, of Chandos Crescent, will appear at Southern Derbyshire Magistrates’ Court in Derby on Wednesday (Sep 22).