Three out of four children say they have seen images online that they found scary or disturbing.
Children's charity the NSPCC wants every computer to be sold with software on it that will block children from seeing nasty things online.
It's not just websites the charity is worried about. Film clips and pop-up ads can also be unsuitable for kids.
The charity adds that it can be hard to find and install software on computers to make them safer for children.
One boy posted a message on the NSPCC website saying: "I've seen violent images I didn't search for. I was freaked out."
The NSPCC also wants more done to get the nasty images taken off the internet.
Sites need to act more quickly
It says that social networking sites and websites that people use to watch videos on should act more quickly when they know there are problem images.
Those sites also need to make sure that it's easy for young surfers to complain if they see things they're not happy with.