Keith Towler said there was little regulation and control of bullying on social networking sites.
A survey suggested over a third of 11 to 17-year olds in Wales who had been bullied had suffered cyberbullying.
The Welsh government said it was better to develop respectful relationships than criminalise bullying.
Cyber-bullying has been highlighted in the media in recent months after the death of 14-year-old Hannah Smith, from Leicestershire.
She killed herself, according to her family, because she was bullied on the social networking site ask.fm.
Under UK legislation there is not a specific law which makes cyberbullying illegal, although it can be considered a criminal offence under legislation such as the Protection from Harassment Act and the Criminal Justice and Public Order Act.
Mr Towler said he believed legislation specifically to deal with cyber-bullying was now needed.
"What we are trying to cope with is an ever-changing world," he told BBC Wales' Welsh language Taro 9 programme.
"We're trying to run to catch up to something that is actually way out there and it is way out there without very much regulation or control, and do we need to wrestle back some control of this so that it is safe? Yes we do."
He told the programme: "I think we need to think about legislation, we need to think about guidance, we need to think about the roles of schools, what is the role of parents and carers, enabling children and young people to empower themselves so that they can take some responsibility for their own safety.
Ysgol y Cymer in Porth, Rhondda Cynon Taf, is one school taking a pro-active approach to try to stop its pupils becoming victims of cyberbullying.
Under a scheme called Cymer Ofal, pupils are able to give advice to other younger pupils on Bullying and cyber-bullying.
One counsellor, Lowri Mitchinson, 16, who was bullied on ask.fm, said her experience could be used to help others.
"Some people don't see teachers as real people who actually care for you. But maybe if someone who has been in their shoes gives them advice then they might listen a bit more," she said.
"I've had the experience myself so they won't just ignore me - they'll know she's been through this, she can help me with this.
"People used to call me anorexic - I wasn't but that could have hurt me so much, and maybe cause me to put weight on or lose it."
"All of those things need to happen."
Olivia Edwards, 15, from Treorchy in Rhondda Cynon Taf, was bullied last year on ask.fm but did not know who the perpetrators were because the comments were posted anonymously.
"I had to read stuff like 'kill yourself' and 'you're anorexic' and stuff like 'you're not pretty'," she said.
"It just really upset me a lot and I started to believe it. It wasn't a good idea to start believing stuff like that."
The bullying ended after two months but she said anyone suffering like she did should delete their accounts on the site.
When asked to respond to the points raised in the Taro 9 programme, ask.fm said in a statement: "We are committed to doing everything we can to protect our users.
"We are working with the pre-eminent online child safety expert Annie Mullins OBE to review and update our safety and privacy policies.
"This will ensure that our abuse and inappropriate content reporting systems are among the most effective in the industry."
The site is also asking users to report any bullying, insisting that complaints will be "dealt with immediately".
A recent survey of nearly 1,000 children and young people in Wales by the Children and Young People's Assembly for Wales: Funky Dragon - an umbrella organisation promoting the rights of young people - appeared to show the scale of cyberbullying.
We're talking about online bullying and that's a situation where a person and in some instances a group of people use emails, the internet or any kind of digital technology to bully someone.
It could involve teasing, upsetting or humiliating and the thing is with this sort of bullying it's there 24 hours a day, seven days a week.
There was a time when you could say bullying ended at the school gate but that's not the case any more.
The other thing about online bullying is that you don't always know who's responsible because it can be done anonymously and there are examples of people setting up fake accounts and hiding their IP address or even blocking their mobile number.
Parents need to be aware of what their children are doing online, understand what they're doing and make sure their children are happy to talk to them if there's a problem with bullying.
Some 47% said they had been bullied and 37% of those said that they had suffered from cyberbullying.
It also suggested it was more of a problem among girls, with 43.8% reporting it compared with 27.4% of boys.
Responding to the call for legislation, the Welsh government said developing positive and respectful relationships would be a better approach.
"We have published Respecting Others, a suite of comprehensive anti-bullying guidance which includes a specific section on cyberbullying," a spokesperson said.
"The guidance gives details of schools' legal responsibilities while providing them with information they need to create effective strategies for tackling bullying.
"There are already a number of criminal laws that can apply in terms of harassment or threatening behaviour, including threatening and menacing communications.
"Rather than criminalise bullying the focus should be on developing positive and respectful relationships amongst children and young people."
Taro 9 is broadcast at 21:30 BST on S4C on Tuesday with English subtitles.
Legislation should be brought in to deal with the problem of cyberbullying, according to the children's commissioner for Wales.