A significant minority of students (17%) were victims of some sort of sexual harassment during their first week of term, a survey suggests.
Sexual comments, wolf-whistling when students walked into lectures, heckling in nightclub queues and jokes about rape were all cited as examples.
The National Union of Students' poll also found two-thirds of students were unaware of how to report abuse.
Universities UK said sexual harassment had "no place" on a university campus.
Students who took part in the survey said the majority (59%) of these incidents of harassment had happened at social events or nightclubs, while a third (33%) had happened in university halls of residence.
It also found two-thirds (66%) stated they were not aware of the procedure to report these incidents and 12% felt they would not be taken seriously if they did.
And 61% said they were not made aware of any codes of conduct implemented by their university, with a further 29% not sure.
The poll of 2,670 students aimed to find out the extent to which students had either been victims of or witnesses to sexual harassment during their first week of term.
Of those who responded, 46% were male and 52% were female; nearly three-quarters (73%) of the respondents were aged between 18 and 20.
NUS women's officer Susuana Amoah said: "It's extremely worrying, but not surprising, that so many students in their first term of university have experienced sexual harassment or seen it happen to somebody else.
"NUS has been working over the last five years to bring sexual harassment on campus to the forefront of the national conversation, and make sure institutions are taking it seriously.
"Reporting systems for sexual harassment are either lacking or not visible to students in a lot of cases, and this needs to change.
"We are working with nine students' unions who have audited their own processes and those of their institutions, and we will be supporting many more to carry on this work until students feel aware of how to report sexual harassment, and safe and confident that their concerns will be taken seriously."
The university umbrella group Universities UK said that sexual harassment had no place on a university campus.
"These are serious matters where a zero-tolerance approach is required. Universities across the UK already have a range of initiatives and policies in place to address these issues," a spokesman said.
"Over the last few months, Universities UK has started work on a programme to see whether there is more we can do to support universities in this area and share best practice across all universities.
"A taskforce is being established to look at various forms of harassment, although specific emphasis will be given to tackling sexual harassment against students and 'lad culture', hate crime on the basis of religion or belief and homophobia."