Oxford University has drawn up a contract which would legally bind students to attend lectures and prevent them suing the institution.
Colleges have yet to decide whether to adopt the contract
A university spokeswoman said the draft document, drawn up by Oxford's Conference of Colleges, was intended to protect both the colleges and students.
Oxford's 39 self-governing colleges had been recommended to adopt it.
But the university students' union said it had asked colleges not to discuss it until students had been consulted.
The contract, written by the president of Trinity College, Michael Beloff QC, will come into force for students accepting places this academic year if the colleges take it up.
It comes as universities across England prepare to charge students so-called top-up fees of £3,000 a year, from this autumn.
The spokeswoman said there had always been an informal "contract" between students and the colleges but a more formal arrangement had been planned for the past four to five years.
She said: "It was decided that it would be helpful for both sides to have it clarified."
She added: "There is the possibility that somebody [a student] could be taken to court but that is really a last resort.
"It is to protect both the college and students. If a student took the college to court saying they didn't receive adequate tuition there is this contract there."
It is up to each college to decide if it adopts the contract, and in what form.
But the president of Oxford University Students' Union, Emma Norris, said the contract in its draft form left students vulnerable because the promises on the university's side were too vague.
The draft commits a college to "make such teaching provision for undergraduate students as it reasonably decides is necessary for their course of study."
A college would also agree to provide library facilities and residential accommodation as well as breakfast, lunch and dinner.
In return, students would promise to pay their fees and abide by the regulations in their college handbook.
But Ms Norris complained of a lack of consultation among students and said: "It doesn't say that the colleges will provide a stated level of accommodation or teaching."
She added: "We don't have a problem with a contract as long as it provides for the students."
She said the students' union had spoken to the heads of colleges who had agreed not to discuss the contract until students had been consulted.