The Charity Commission is to help draw up new guidance on free speech at universities after a parliamentary committee described its current approach as "unduly restrictive".
The regulator will work on the guidance with other organisations, including the Office for Students, the National Union of Students, Universities UK and the Department for Education.
About 120 students' unions are charities and therefore regulated by the commission. But its current guidance on free speech has drawn criticism.
Sam Gyimah, the universities minister, said in February that the commission "needed to ensure its rules are clear and don't discourage student unions from hosting controversial speakers".
The following month a report on free speech in universities by the cross-bench Joint Committee on Human Rights, which is chaired by the Labour MP Harriet Harman, described the commission's advice as "not easy to use" and "in places unduly restrictive", and said it "could deter free speech".
In its written response this week to the JCHR report, the commission pledged to "collaboratively contribute to new guidance", which it said would act "as a single reference point to streamline and signpost information to universities, students and students’ unions on their respective rights and duties on free speech".
The commission additionally agreed to review chapter five of its guidance, Protecting Charities from Harm, "to make sure it sufficiently stresses what charities can do".
It will also review internal staff guidance on students’ unions "to ensure it sufficiently reflects relevant aspects of freedom of speech when students’ unions carry out activities".
Helen Stephenson, chief executive of the commission, said in a statement: "I am absolutely clear that charitable students’ unions, universities and other higher education providers can challenge traditional boundaries, encourage the free exchange of views and host speakers with a range of opinions, including those who might be controversial or divide opinion.
"These activities are entirely in line with their aims to promote education. Our role as regulator is to provide guidance that enables trustees of all charities to carry out their activities while complying with their legal duties and responsibilities as charities and, where necessary, hold trustees to account against that guidance."
Stephenson was among the attendees at a free speech summit hosted by Gyimah on 3 May.
Gyimah told delegates there was "a risk that overzealous interpretation of a dizzying variety of rules is acting as a brake on legal free speech on campus".
The commission's response to the JCHR report pointed out it had never opened a statutory inquiry into any students' union or exercised any of its compliance powers.
It added: "We believe the charity law rules are very clear, but we recognise that trustees may find the judgements they may have to make in applying them, in a small number of occasions, challenging."
"We will reflect further on the committee’s view that our guidance does not place due weight on the fact that inhibiting lawful free speech could damage a students’ union’s reputation."