They warned there are still "critical unknowns" surrounding how effective the vaccine is against transmission.
The health body was also concerned that the demand for the vaccine from travellers could lead to an inadequate supply and leave "priority populations" at risk of severe illness.
The WHO's position was laid out in an interim position paper published here.
The paper said: “At the present time, it is WHO’s position that national authorities and conveyance operators should not introduce requirements of proof of Covid-19 vaccination for international travel as a condition for departure or entry, given that there are still critical unknowns regarding the efficacy of vaccination in reducing transmission.
“In addition, considering that there is limited availability of vaccines, preferential vaccination of travellers could result in inadequate supplies of vaccines for priority populations considered at high risk of severe Covid-19 disease.
“WHO also recommends that people who are vaccinated should not be exempt from complying with other travel risk reduction measures.”
It comes after Professor Jonathan Van-Tam said the government is looking at the issue of vaccine passports but added that he thought there were “plausible arguments for and plausible arguments against”.
The deputy chief medical officer told ITV’s Good Morning Britain it is not appropriate for him to give his personal views, but the Government has to balance really difficult decisions, adding that we have “never lived in a society here, where we force medical treatments upon people”.
Indeed, Education Secretary Gavin Williamson said that Michael Gove had been tasked with looking into vaccine passports.
“Michael Gove is being charged with actually looking at this", he told LBC. There are many challenges with this and it’s really important to look right across the spectrum, at both the benefits it would bring but also some of the challenges it could bring.”
Mr Williamson suggested he would accept a vaccine passport to get back into theatres, restaurants and cinemas.
He said: “I think I would probably do pretty much sort of anything to be able to enjoy all those lovely things.
“I think the idea of going to a restaurant with your family or going to the theatre is something we all really want to see.”