The teenager has links to the Glenrothes, Edinburgh and Musselburgh areas, where she may have travelled by bus.
Police Scotland said: “We are appealing for the public’s help as part of our efforts to trace a teenager reported missing in Kirkcaldy.
“Sophia last seen leaving an address in the Rimbleton Park area of Glenrothes around 1100 hours on, Monday 1st March 2021.
“The 13-year-old, who lives in the Kirkcaldy area of Fife, has not been seen since and there are growing concerns for her welfare.
“Sophia is described as white, 5ft 5” tall, of average build, with long brown hair likely in a ponytail.
“When last seen, Sophia was wearing light grey jogging bottoms and dark grey hooded top. She was carrying a large black shoulder bag.”
Anyone with information is urged to contact Police Scotland via 101, quoting incident number 1268 of 1st March 2021.