The Year Five pupil was walking to Wavell Community Junior School from Rutland Road in Catterick when she saw a man in the area who started to follow her.
The incident happened at around 8am.
The girl rushed to school and reported the incident to staff at the school, who subsequently reported it to the police.
The man is described as being white, well-built, shorter than 6ft, witg no facial hair and in his thirties. He was wearing a black coat, dark fishing type hat and grey jogging bottoms.
Sergeant Sharon Findlay from the Local Neighbourhood Policing Team said: “We do not want people to panic and be alarmed. This in an unusual occurrence and we are conducting enquiries to establish the full circumstances surrounding the incident.
“Residents should feel reassured we are conducting high visibility patrols in the area and we encourage anyone with any information to get in touch”.
“Anyone who saw the man described in the area at the time of the incident is asked to contact police. Dial 101, press 1 and speak to the force control room. Please quote incident number 12180218718 when passing on information."