Children who use self-deprecating humour among their peers are more likely to be bullied, researchers say.
A study from the University of Keele has examined links between bullying and different styles of playground humour.
It found that some positive types of humour were used by children to raise their status and show social skills.
But researchers found children who were victims of bullying were more likely to make "self-defeating" jokes at their own expense or about their appearance.
The boundaries between bullying and teasing and "just joking" have always been blurred, but this study of more than 1,200 children aged 11 to 13, has examined how different forms of humour are associated with bullying and aggression.
Psychologist Dr Claire Fox says that humour can be deployed positively as a weapon to prevent bullying.
She says the "class clown" can be a classroom success, demonstrating their "social competence" by making other people laugh and telling funny stories.
This is known as "affiliative" humour - one of four types of humour identified by researchers - and it is seen as a positive type of joking.
There is also another type of positive humour, known as "self-enhancing", which is where joking is used as a way of coping and reducing anxiety by laughing about something that otherwise might be frightening.
But the bad type of humour associated with bullying victims is "self-defeating", which is where children disparage themselves excessively and make themselves the butt of their own jokes.
This is characterised by children saying: "I often try to get other people to like me more by saying something funny about things that are wrong with me or mistakes that I make."
Dr Fox says that this becomes a vicious circle, with bullied children confirming a negative view of themselves.
Making fun of themselves or some aspect of their character or appearance does not make them more endearing or popular, instead it is seen as undermining their status and self-esteem.
The fourth type of humour, identified as "aggressive", shows another form of negative joke telling. In this type of humour, children use jokes as a way of attacking other people.
This is described as: "If someone makes a mistake, I will often tease them about it."
The study, funded by the Economic and Social Research Council and involving academics from Strathclyde University and Oxford Brookes as well as Keele University, looked at bullying in physical and verbal forms and in relationships, such as social exclusion.
The researchers want to see if children can be taught to change their style of humour as part of avoiding this negative way of labelling themselves.
"What our study shows is that humour clearly plays an important role in how children interact with one another and that children who use humour to make fun of themselves are at more risk of being bullied," says Dr Fox.
"We know that this negative use of humour is a nurtured behaviour, influenced by a child's social environment rather than genetics.
"This makes the behaviour easier to change, so we hope the next step for this study is to see whether it is possible to 'teach' children how to use humour to enhance their resilience and encourage them to not use negative forms of humour."