Two staff who were suspended from work over claims they tied up a student's arms and legs have left the school involved, a spokeswoman said.
The school said the staff members had left as a result of the incident
The pair were alleged to have bound a sixth-form pupil and left him for several minutes at Folkestone Academy in November.
A spokeswoman said the teacher and instructor involved had left the academy's employment as a result.
The end-of-lesson "prank" was filmed by other students on their mobile phones.
In a statement the school said: "On Wednesday 28 November 2007 an incident occurred at the Folkestone Academy in which a student was tied up with plastic cable ties by a teacher and an instructor.
"The incident came to light the following week and the two members of staff were immediately suspended.
"As a result of the incident, the two staff involved have now left the academy's employment."
The school added the student, whose name has not been released, had since returned to the Sixth Form, but it was not yet clear whether he would complete his studies.
The pupil's parents are unhappy and feel the school and police did not take enough action.
His step-mother Linda Rolfe said: "It's criminal what they done. They shouldn't have done it in the first place. And they call themselves teachers, I'm so annoyed with it all."
In a letter sent to parents in December, principal John Patterson said although the incident may have been "intended to be good humoured", the academy saw the alleged behaviour as "totally inappropriate".
The incident was referred to Kent Police who confirmed at the time that they would not be taking the matter any further.
The £38m purpose-built academy opened in 2007 and replaced the town's Channel School.
Specialising in art, media and European culture, the co-ed state secondary school has 1,080 pupils.
Designed by architects Foster and Partners, it is said to have some of the finest school buildings in the country.