Childnet International says webcams should be disconnected when not in use, and teenagers should not leave webcams in bedrooms or other private areas.
A BBC Radio 5 live investigation found sites where hackers exchanged pictures and videos of people captured on their own webcams without their knowledge.
A police spokeswoman said webcam hackers would be prosecuted.
Commons Home Affairs Committee chairman Keith Vaz urged teachers to talk to pupils about the dangers of using webcams, and computer manufacturers to improve security for users.
But some experts have expressed doubts about how widespread webcam hacking is and stressed that anti-virus software plays a vital role in preventing it.
The BBC Radio 5 live team found a thriving black market where access to compromised computers was bought and sold for a few pence.
Student Rachel Hyndman, 20, from Glasgow, who has a part-time job in a computer shop, believes she was the victim of webcam hacking.
She spotted the camera on her laptop had switched itself on while she was watching a DVD in the bath.
She says: "I was sitting in the bath, trying to relax, and suddenly someone potentially has access to me in this incredibly private moment and it's horrifying.
"To have it happen to you without your consent is horribly violating."
Hackers are able to gain access to victims' computers using a piece of malicious software (malware) called a remote-access Trojan (Rat).
Many Rats now include a function allowing a hacker to access the victim's webcam without their knowledge.The malware is spread in infected files or by tricking the victim - known as a "slave" or "bot" - into visiting a specific webpage.
WEBCAM SAFETY TIPS
- Webcams can be affected by viruses so be wary of emails and social network messages from strangers
- Make sure anti-virus and firewall protection is kept up to date
- Avoid putting webcams in bedrooms or other private areas
- Unplug the webcam, cover the lens or point it at a blank wall when it is not in use
- Be sure you can trust the person you are chatting to and remember webcam footage can be recorded and potentially shared online
- If you have been the victim of inappropriate sexual contact via webcam tell a trusted adult and report it to the police via the Child Exploitation and Online Protection centre (Ceop)