The incident took place last evening when the victim fell from Gold Crest Views building in Jumeirah Lake Towers, the Emirates 24/7 Online reported.
The body of the girl, who was not named in the report, was discovered by a building cleaner who informed his manager following which police was called.
The Bangladeshi cleaner identified the girl as a resident of one of the penthouses in the building.
The area behind the building, overlooking the lake, has been cordoned off by the police, who are questioning the building's managers, cleaners and residents about the incident, the report said.