Whether it's due to popular teen films such as Mean Girls or gender stereotypes most people imagine girls form more cliques than boys.
Yet a new study contradicts this, suggesting that boys are more likely to form tight-knit friendship groups.
Researchers say analysing social mixing patterns is important for infectious diseases and vaccination planning.
They found that boys were more likely to mix with the same six friends over a period of six months.
Girls' friendships, however, were more variable.
The study, published on Wednesday in scientific journal Plos One, was led by the London School of Hygiene and Tropical Medicine (LSHTM) in partnership with the University of Cambridge.
Scientists use complex mathematical models to look at how diseases spread through social groupings.
And this research could help predict more accurately how they will spread - and might one day lead to changes in advice on how infectious diseases are controlled.
Researchers asked 460 Year 7 pupils across four UK secondary schools representing a range of socioeconomic areas to name the six children they spent most time with daily, between January and June 2015.
Lead author Dr Adam Kucharski said: "Showing boys are potentially more cliquey than girls, perhaps going against gender stereotypes, and that popular children remain popular over time, is an interesting social insight - but for mathematical modellers this type of information is also extremely valuable.
"Understanding age-specific social mixing patterns is vital for studying outbreaks of infectious diseases like flu and measles, which can spread rapidly, particularly among children.
"Mathematical models that predict the spread of infectious diseases are now an essential part of public health decisions for the introduction of new vaccines."
Another of the study's authors, Dr Clare Wenham, now assistant professor in global health policy at the London School of Economics, said: "Kids are a very important part of looking at how diseases spread.
"Previous studies have only looked at how children mix over one day, so with this study we wanted to see how it changed over time.
"It would also be good to extend the study over a longer period to see how friendship groups changed over the years."
Dr Terri Apter, a psychologist and former Cambridge tutor, who has written extensively on teenagers and friendships, said: "It has been observed that boys' friendships are more stable and girls' are more volatile.
"As a result, girls might feel more pressure to have 'just in case' friends in case they fall out with their best friend and they feel more social pressure to be friendly with people that aren't really their friends than boys.
"All this leads to a larger, more changeable group."