Less than 20% of parents supervise their children's use of social media, according to findings contained in research released today by the National Anti-Bullying Centre at DCU.
It found that more than half of parents did not know how to block inappropriate web content.
The survey also found that while most parents use Facebook, they are unfamiliar with networks used by kids, like Snapchat.
Dr James O'Higgins of the National Anti-Bullying Research and Resource Centre says it is vital parents get to know where their kids are "hanging out" online.
Dr O'Higgins said: "In real life, outside the internet, parents wouldn't bring their kids to a park and leave them in a playground to play and go to the pub to socialise in a different space.
"Certainly, unless they made sure the kids were safe and supervised and had the tools to protect themselves."