North Yorkshire Police said it was called by Yorkshire Ambulance Service to the incident in the Malton area at around 4.15pm on Monday, November 1.
A force spokesperson said: “It happened inside the family’s home.
“Despite the efforts of medical professionals and a member of the public who came to the family’s aid, tragically, the girl died at the scene after suffering serious injuries.
“Following the incident, the dog was secured inside a car by a family member prior to the arrival of the emergency services.
“It was then seized by officers who took it to secure kennels where it remains at this time.
“The dog is being assessed as part of the investigation.
“Our thoughts remain with the girl’s family and friends at this very distressing time.
“Officers are supporting the family while enquiries continue.
“We also urge people not to speculate about the incident, respect the family’s privacy and allow them to grieve in peace.
“We will provide more information when we are able to.”
