From July, all loss-making courses at the university’s Centre for Community Engagement (CCE) will be axed.
Summer school activities, sign language classes and deaf studies will continue at the centre, but evening classes and other part-time adult education courses will end.
The closure puts at risk the jobs of the centre’s 12 academic staff, three administrators and 1 associate tutors unless they can be relocated within the university.
Sussex has blamed changes to higher education funding for the closure, saying it is not feasible to subsidise the centre’s ?350,000 annual loss using fees from full-time students.
But the centre’s supporters have urged the university to reconsider the decision and 1,500 people have signed an online petition against the cuts.
Andrew Gammon, who gained a diploma in archeology from the centre, said the decision was “short-termist”.
“I understand the economic reasons given for why CCE cannot be kept going exactly as it is,” he said.
“But a more creative imaginative approach is needed - not just one that sees the possibilities of keeping the centre going as it is or effective closure.
“The university is committed to widening participation and access. This should be geared not just to young students, but also to adult learners, part-time learners and the local community.”
Michael Farthing, vice-chancellor of Sussex, said the courses earmarked for closure were mainly leisure-based and did not lead to professional qualifications or progression to degree course.
“We regret that this proposal would end evening classes and day schools which have been enjoyed by local people over the years”, he said.
“However, given the government’s policies regarding the funding of higher education, the university can no longer support such courses.”