Police are extremely concerned for the welfare of the girl aged 12 and would urge anyone who has seen her call them immediately.
Officers say she has gone missing with her mother, however, there are serious concerns for the daughter.
Police say that Thandiwe Kombe Kanyanta, 12, was last seen on Tuesday, 18 July.
Thandiwe is described as black and of slim build. It is not known what she is wearing.
She is believed to be with her mother, 30-year-old Chileshe Wendy Kanyanta with whom she lives.
Chileshe is described as black and of medium build.
Officers believe that they may have left the south London area and may be in the Liverpool area.
Officers are concerned for Thandiwe’s welfare and ask anyone who has seen her to call police.
Anyone with information on their whereabouts should call police at Bexley via 101 or @MetCC