Activate Learning has announced 64 redundancies across its Reading College, Banbury and Bicester College and City of Oxford College campuses.
Unite union and University and College Union claimed this would result in reduced teaching hours.
Activate Learning said its current provision would be "maintained" and funding was reduced as a result of fewer students taking up places.
"We recognise that this is a difficult time for staff, particularly those faced with the prospect of redundancy," said chief executive Sally Dicketts.
"We are however seeking opportunities to minimise the impact, for example through job sharing or voluntary redundancies."
Teaching, technical and library staff gathered outside Reading College in Kings Road on Wednesday holding placards and banners.
They said the redundancies at the site, which provides entry level courses through to degrees and apprenticeships, will result in fewer opportunities for students.
The group chanted: "No ifs, not buts, no education cuts."
College staff have staged a protest over funding cuts and redundancies.