The attorney general's office said yesterday the girl died after being transferred for treatment to a hospital in Cincinnati, Ohio.
She was one of nine girls transferred for treatment to hospitals in the United States.
Nineteen of the adolescents perished at the scene of the March 8 fire and 22 others have died at hospitals.
The fire began when mattresses were set ablaze during a protest by residents at the overcrowded youth shelter.
Guatemalan authorities have arrested three former child welfare officials who were responsible for overseeing the youth shelter.