The incident at The Dukeries Academy in Ollerton happened on the first day back after the Christmas break.
It was reported that the pupil, who is 13, had brandished the sharp kitchen knife on school grounds in front of other pupils.
She was then heard to say ‘I’ve got to get out of here’ before running off.
A police liaison officer was at the school at the time and dealt with the situation.
The school have confirmed that the pupil’s future at the school is being considered, but has not returned since.
Principal Ian Barton said: “We can confirm there was an incident at The Dukeries Academy where a student brought a knife into school.
“Once our staff were aware of this, they respond quickly and took appropriate action.
“The student did not directly threaten any other children and no one was injured.
“This vulnerable student has not returned to school and we are working with our colleagues from relevant external agencies to consider their future and well-being.
“Please be assured that the safety of our students and staff will always be our first priority and we take every precaution possible to ensure they are secure and well cared for. I understand the concern this may have caused our parents and my door is always open to them to discuss any worries.”
A police spokesperson said: “School liaison officer, Pc Manson, was already at the academy when she was notified that a vulnerable female student was outside in the quad area with a knife.
“The girl was quickly isolated, searched and removed from the school to a place of safety. No students were threatened or injured during the incident.”