Zac Bolland, 23, of Blackleach Drive, Worsley, has been charged with three counts of murder, four counts of attempted murder and one count of arson with intent to endanger life.
Courtney Brierley, 20, of Worsley Avenue, Worsley has also been charged with the same offences.
They are both in custody and will appear at Manchester and Salford Magistrates' Court later on Wednesday.
The early morning fire at a house in Jackson Street, Worsley, on Monday trapped seven members of a family inside.
Demi Pearson, 14, Brandon Pearson, 8, and Lacie Pearson, 7, all died.
The children's mother, Michelle Pearson, 35, is in a serious condition in hospital and a fourth sibling, three-year-old Lia, is critically ill.
Ms Pearson is understood to be heavily sedated and does not yet know her children have died.
Two 16-year-old boys - Ms Pearson's son Kyle and a friend - managed to escape.
Kyle reportedly tried to get back in to help his family but was beaten back by flames and smoke.
Sources have told the Press Association that the family had been living under threat, and security measures, including a device on their letterbox, were in place.
Known as target hardening, such arrangements are usually used to protect a building in case of an attack.