Support and service staff in Trinity College have voted by more than 92% in favour of industrial action.
Trade union Unite, which represents the workers, has said it could include strike action.
They said the ballot followed the university’s decision to "unilaterally halt future promotions" for the employees, while also employing future staff on five-year contracts rather than permanent contracts.
Unite's David Grouse said: "The overwhelming vote for industrial action indicates the level of anger among Unite members.
"Support and service staff have made it clear that they will not allow management to attack their working terms and conditions without a significant response.
"We remain available to meet with management to discuss the issues causing this dispute, and we call on them to genuinely attempt to resolve these issues."
Committee Secretary Cieran Perry said the result gives the union a clear mandate for strike action.
He said: "We will have no hesitation in pursuing this option if management aren’t willing to genuinely engage with Unite."