"Men can wear dresses, women can wear suits, and non-binary people are free to define the outfits that feel most appropriate to them in a formal setting," Northrup told the Cambridge University student newspaper, Varsity
The head of a college at one of Britain's oldest universities has rewritten a 650-year-old dress code to allow transgender students to dress how they choose at formal events with campaigners hoping other colleges will follow suit.
Mark Elliot, the dean of St Catharine's College at Cambridge University, reworded the dress code after a campaign spearheaded by American transgender student Charlie Northrup, who transitioned from male to female earlier this year.
Previously male students had to wear smart trousers and jacket with a tie at formal events while women had to wear a skirt and blouse or dress but now students can choose to wear what they like as long as it is "suitably smart dress".
"'Smart dress' is defined without reference to considerations of gender identity or expression," states the revised dress code published on the college's website.
A spokesman from the college declined to comment further.
Northrup welcomed the move that comes as transgender rights become hotly contested globally with U.S. President Barack Obama notching up a presidential first by using the word "transgender" in this year's State of the Union address.
"Men can wear dresses, women can wear suits, and non-binary people are free to define the outfits that feel most appropriate to them in a formal setting," Northrup told the Cambridge University student newspaper, Varsity.
The post-graduate student studying classics later tweeted: "Even changing the world in a small way feels extraordinary - Congrats @Catz_Cambridge."
The student newspaper said the dress code campaign was a combined effort and was "inspiring other Colleges to adopt a similarly progressive ethos".
A recent report by rights group ILGA-Europe said some countries have made strides towards giving lesbian, gay, bisexual, transgender and intersex (LGBTI) people legal equality but transgender people can face discrimination in employment, education and healthcare and still face widespread violence.
The United Nations heard earlier this month that progress towards giving LGBT people legal equality had been overshadowed by "brutal" and "grotesque" homophobic and transphobic violence which often goes unreported.