Five students have been suspended from the University of Sussex for leading the occupation of a building in protest over the working conditions of staff.
Students occupied part of Bramber House in support of Tuesday's national strike by lecturers and administrative staff.
The university said it took the action because protests had been characterised by "violence and intimidation".
The students said the measures were "draconian" and those involved in the sit-in left peacefully on Wednesday.
'Management are scared'
About 30 people entered the building on 25 November to support the national strike by university staff over a 1% pay offer and call for an end to the privatising of some support services at Sussex.
On Thursday scores of students held a demonstration on the campus at Falmer calling for the five suspended students to be reinstated.
In a statement on their Facebook site, they said: "Clearly, they have singled out five students for their involvement in a movement of students and staff fighting for a more democratic university.
"Draconian suspensions are not democratic.
"Management are scared by staff and students protesting for a more democratic university."
A seven-week protest at Bramber House led to clashes with police and bailiffs in April.
The university's registrar, John Duffy, said: "We fully support students' rights to protest lawfully. There have been regular demonstrations on a range of issues that have passed off peacefully.
"But the university has been very clear that we will not tolerate any violence, intimidation or serious disruption. Unfortunately, we have seen all three of these kinds of behaviour once more take place in connection with the recent occupation and subsequent events."
He said there had been three "disruptive occupations" on the campus since February 2013, signifying a "persistent pattern".
He added: "This week we sought and were given a court order that made it clear that the occupiers had no right to be there. The occupiers did not attend court to defend their actions.
"But in the circumstances of this persistent disruption, we feel we need to go further to ensure there is no repeat of the appalling behaviour that has characterised these events."