Professor Daniel Miller is one of team of eight ethnographic researchers based at University College London who are working on a study across seven countries including India, China, Brazil and the UK to examine social media trends.
Miller said the social networking site was "simply not cool any more".
"What we've learned from working with 16 to 18-year-olds in the UK is that Facebook is not just on the slide, it is basically dead and buried," said Miller.
Children and teenagers are increasingly communicating through newer contenders such as Twitter, Instagram, SnapChat and WhatsApp.
The young people are apparently logging off to avoid the stigma of using the same site as the older generation - and to keep their indiscretions private from relatives, 'The Times' reported.
"What appears to be the most seminal moment in a young person's decision to leave Facebook was surely that dreaded day your mum sends you a friend request," he wrote on the website theconversation.com.
"Parents have worked out how to use the site and see it as a way for the family to remain connected. In response, the young are moving on to cooler things," he wrote.
Miller said the switch was taking place despite the fact that none of the rising stars of social media apps can match Facebook for ease of use.
"In my school research, the closest friends are connected to each other via Snapchat, WhatsApp is used to communicate with quite close friends and Twitter the wider friends. Instagram can include strangers and is used a little differently," said Miller.
"Facebook, on the other hand, has become the link with older family, or even older siblings who have gone to university," he said.
"I don't expect Facebook to necessarily disappear altogether. But I think it's finished for the young in the UK and I suspect other countries will follow," Miller said.