Leona Peach was last seen in the Hele Park area of Newton Abbot in Devon on the morning of Monday December 20.
It is believed she may have left home to be with her father Billy Peach, who lives in Bideford, north Devon.
Devon and Cornwall Police are appealing for Mr Peach or Leona to get in touch with them, or Leona’s family in Newton Abbot, to let them know she is safe.
Members of the public with any information on their whereabouts are also asked to come forward.
Leona is white, around 4ft 9in, of slim to medium build with hazel eyes.
She has long, light-brown hair and a bald patch above her right ear.
Leona was last seen wearing grey or blue leggings or skinny trousers, a dark-coloured fur coat, flip-flops and was carrying a pink bag.
Detective Inspector Dave Pebworth said: “Inquiries are continuing in our efforts to locate Leona and we are asking the public to help us.
“We would ask Mr Peach to get in touch as we believe he may be able to help us with our inquiries.
“We are supporting her friends and family and are appealing to Leona to contact home so that they know that she is safe and well.
“We would ask that anyone who is with her encourages Leona to contact her family in Newton Abbot.
“Leona if you are reading this, we want you to know you are not in any trouble, please contact us, or someone you trust, to let us know you are safe.”
Anyone with any information should contact police on 999 quoting log number 0222 of December 20.