Gina Rosvold was last seen at about 9pm on Saturday 5 December 2020.
The 17-year-old is described as being 5 foot 5 inches tall with a medium build, green eyes and shoulder length, black hair.
She was last seen wearing a blue knee-length dress with white flowers and has links to the Faversham area.
Officers are concerned for her welfare and they appealing for anyone with information on her whereabouts to contact Kent Police.
Anyone who has seen Gina or knows where she might be is asked to call 101 quoting 05-1118.