Zoe Dunn, 17, was last seen in the Ingram Road area of Gillingham at around 11am on Wednesday 13 December 2023.
She was dressed in black clothing including a coat and tights.
Zoe has links to the Ashford and Broadstairs areas and may be travelling by bus or rail.
Officers are concerned for her welfare and would like to hear from anyone who sees Zoe or knows where she is.
Please call 999 quoting reference 13-0544.