Homosexuality is not illegal and increasingly recognized in Vietnam. Although same-sex marriage is not yet legalized, many Vietnamese, especially the young people, have a more positive attitude towards gays and lesbians with more and more people willing to admit that they are homosexual. In fact, several movies on this theme made by Vietnamese local producers have won great international prizes and award.
Like some other Asian countries, Vietnamese men wear pink often and that should not be mistaken for being queer. In general, most clothes are accepted but men should avoid tight-fitted clothes and make-up.
City dwellers tend to have more open-minded views towards sexual orientation and most queer-friendly bars and clubs are located in Hanoi and Ho Chi Minh City. You would surely find address of those lively places on Lonely Planet guidebooks. Some suggestions could be Golden Cock and Apocalypse Now bar in Hanoi and Q bar in Ho Chi Minh City.