Firefighters are calling the fire suspicious but are still investigating what happened.
A neighbor called 911 around 9:40 a.m. after they saw smoke coming from the back of the home.
"The minute I came out from my back door, I looked over there and I could see the smoke," says neighbor Gail Hanson.
When firefighters arrived, they say they found a 13-year-old girl unconscious in her room.
"They were able to bring her out and begin resuscitation efforts on her. She does have some burns and she was in cardiac arrest when she left the scene," says Phoenix Fire Captain Jonathan Jacobs.
The victim was taken to a hospital to be treated for the possible cardiac arrest and some burn injuries from the fire. She later died. Neighbors said the girl lives with her mother and two younger brothers, but no one else was home during the fire.
Police say officers were called out to the home at 1 a.m. because of an argument of altercation between the teen and her mother. But it's not clear what, if anything, that has to do with the blaze.Hanson says all three kids, the girl and her brothers, should've been in school.
"If I would have known someone was in there, I would have jumped in and gotten her," she says.