Members of the University and College Union (UCU) said millions of students were taught by staff with few rights. Two-thirds of university researchers were on temporary contracts.
The union found that in 112 further education colleges, almost a third of teaching staff were on zero-hours deals or similar arrangements.
A study of 75 universities found 17% of teaching staff were on such contracts.
The UCU said staff were exploited by such contracts, under which they are not guaranteed any work.
UCU general secretary Sally Hunt said: "Students in colleges and universities would be horrified if they knew that many of those who teach them have little or no employment rights, no job security and that most of our groundbreaking research staff are without permanent contracts."