Anti-pedophile activism encompasses opposition against pedophiles, pedophile advocacy groups, child pornography and child sexual abuse. Much of the direct action classified as "anti-pedophile" involves demonstrations against sex offenders, groups advocating legalization of sexual activity between adults and children, and internet users who solicit sex from underage teenagers.
In 2000, some local groups took to marching in opposition to the locations of various child sex offenders following a media campaign of "naming and shaming" suspected pedophiles in the United Kingdom. In the Netherlands, the pedophile activist group Vereniging Martijn has been protested against by the far right Nationale Alliantie. In the UK, the far right National Front party was protesting in front of Paedophile Information Exchange conferences in the 1970s and against the Rotherham Muslim paedophilia scandal in 2014, alongside EDL and BNP. There have been incidents in which vigilantism intended to be against pedophiles has been mistakenly directed against the wrong person, including:
- One concerning a man with the same surname as a locally known pedophile.
- An incident where a man was misidentified as a pedophile because he was wearing a neck brace similar to the one a sex offender was wearing when pictured in a newspaper.
Perverted-Justice is an anti-pedophilia, anti-hebephilia, and anti-statutory rape organization with the stated mission to expose and convict adults who solicit and groom minors on the Internet. The organization goes after adults seeking sexual encounters with minors (the age range chosen for the decoy characters is 10-15). After obtaining identifying information from these men, who may offer their telephone numbers and other details so that meetings can be arranged, the organization passes the information on to law-enforcement.[clarification needed] Some administrators of Perverted-Justice.com launched CorporateSexOffenders.com, and its associated wiki project "Wikisposure," in June 2007, which aim "to target corporations and the pedophiles they allow to use their services." The Wikisposure project later moved to its own domain, Wikisposure.com.
Jewish Community Watch
Jewish Community Watch, a New York City-based organization focusing on prevention of child sexual abuse in the Orthodox Jewish community, received mixed support over their posting the names of suspected pedophiles on their main website. The column titled the "Wall of Shame" listed the names of individuals suspected of abuse, their photos and testimonies from alleged victims.
Letzgo Hunting is an Internet-based anti-paedophilia vigilante group based in Barwell, Leicestershire, England. A man committed suicide days after being accused and "named and shamed" of being a paedophile by the group. Jim Gamble, formerly chief executive of the Child Exploitation and Online Protection Centre has described the activities of the group as "deeply disturbing".
Another initiative, Predator Hunter, headed by Wendell Kreuth, aims to track down and expose the pornography-related activities of alleged 'sexual predators', as disclosed in his interview with Minnesota Public Radio. The activities of Predator Hunter in the prievious years garnered more attention, particularly the actions of Bradley Willman, whose anti-pedophile activism is described below:
Between 1997 and 2001, Brad Willman was known as Omni-Potent, an Internet vigilante who would track pedophiles by spending 16-plus hours a day hacking into people's computers from his parent's house in Langley, a suburban community just outside Vancouver. Ultimately, he was responsible for the arrests of about 40 pedophiles across Canada and the U.S. Willman's successful, albeit unpaid and short-lived venture as "Citizen Tipster," as he was known by police, is now over. But his activities have sparked intense debate over the legality of his tactics.
He would verify where suspects were from, and send the information on to Predator-Hunter, an online pedophile watchdog group that would, in turn, send it to other sources to be verified before passing it on to police. "Parents in a number of countries, I think, owe OmniPotent a debt of gratitude for what he did," says Wendell Krueth, president of Predator-Hunter. The end justifying the means is a concept Predator-Hunter supports. "We don't tell people to go hack, but we consider whatever information we get worthy in taking down pedophiles," Krueth says.
Silentlambs and LambsRoar are both web-based anti-pedophile groups that seek to protect children through education, to provide legal assistance, and to provide assistance to victims [survivors] who have been molested as children and silenced from speaking out or seeking proper assistance as directed by religious authorities. To date, most emphasis has been on abuse within the Jehovah's Witness community.
Members of Anonymous were identified as responsible for the arrest of suspected pedophile Chris Forcand. They contacted the police after some members were "propositioned" by Forcand with "disgusting photos of himself". Anonymous were described as "cyber-vigilantes who seek to out anyone who presents with a sexual interest in children".
Creep Catcher operates in 15 cities across Canada, posing as children in chat rooms to sting, record and shame adults who try to meet them for sex.
Wanted Pedo is the main French association struggling against paedophile networks. Their website have been suspended by justice for exposing paedophile websites.
Internet Interceptors are not actually a pedophile hunter group or activists, but they do give advice and information to pedophile hunters. The people behind Internet Interceptors would like to see pedophile hunters regulated and work alongside the police. 
Criticism of tactics
A representative of the National Center for Missing and Exploited Children's Exploited Child Unit has stated that the NCMEC does not condone investigations by citizens because according to the NCMEC, those actions do not deter predators and can push the predators to move to other locations and become more effective at hiding their identities. The internet safety organization CyberAngels, an offshoot of the Guardian Angels echoes similar concerns. Police officials in the past have been opposed to working with such groups, or have done so only reluctantly.
- Anti-pornography movement
- Chris Forcand
- Letzgo Hunting
- To Catch a Predator - An NBC Dateline series that collaborated with Perverted-Justice
- John Wojnowski
- Maxim Martsinkevich
- Families flee paedophile protests BBC News August 9, 2000, retrieved May 21, 2007
- Dutch paedophiles set up political party Dutch News at Expatica, May 30, 2006. Retrieved January 22, 2012
- "How did the pro-paedophile group PIE exist openly for 10 years? - BBC News". BBC News. Retrieved 2015-10-11.
- "Apologists for paedophiles: How Labour Deputy Harriet Harman, her shadow minister husband and former Health Secretary Patricia Hewitt were all linked to a group lobbying for the right to have sex with children". Mail Online. Retrieved 2015-10-11.
- Thomson, Mathew (2013-11-28). Lost Freedom: The Landscape of the Child and the British Post-War Settlement. OUP Oxford. ISBN 9780191665097.
- "English Fascists Have Descended On Rotherham's Sex Abuse Scandal | VICE | United Kingdom". VICE. Retrieved 2015-10-11.
- "Rotherham Abuse Scandal: National Front and English Defence League Fight on Streets". International Business Times UK. Retrieved 2015-10-11.
- Boulware, J. Plain stupid at Salon, September 27, 2000
- Mob mistakes man for sex abuser at BBC News, 24 July 2000
- Vigilante attack on innocent man at BBC News, 24 July 2000
- "FAQ." Perverted Justice. Retrieved on October 20, 2013. "There is no reason to do that when online predators are so numerous and motivated to contact what they think is a 10-15 year old male or female first."
- Perverted-Justice.com, Official website
- Corporate Sex Offenders, retrieved June 19, 2012
- Silberstein, Rachel."Watching the Jewish Community Watch and Its 'Wall of Shame:' A young man’s brazen blog about alleged child sex-abusers in the Chabad community divides Crown Heights." Tablet Magazine. July 26, 2013.
- Fricker, Martin (18 September 2003). "Gary Cleary suicide: Man hangs himself after vigilantes accuse him of being a paedophile". Daily Mirror. Retrieved 22 October 2013.
- Barford, Vanessa (19 September 2013). "Who are vigilante group Letzgo Hunting?". BBC Online. Retrieved 22 October 2013.
- Chasing online predators, April 15, 2002, retrieved May 21, 2007
- The Big Chill: Verizon's decision last month to shut off a Montreal ISP for hosting edgy gay chatboards points to a colder, grayer internet ahead, November2006, retrieved May 21, 2007
- Howard, Cori Internet Vigilante in Maclean's, Vol. 118, Issue 23 (2005), pp. 56-57 (or at Ebsco portal
- See also Casey, Eoghan, Digital Evidence and Computer Crime: Forensic Science, Computers and the Internet. London: Academic Press, 2004. pg. 580 
- Howard, "Internet Vigilante", pg.56
- "French, Rose Jehovah's Witnesses Settle Abuse Cases Associated Press coverage at Silentlambs (May 10, 2007)
- Gus Kim (reporter) (2007-12-08). "Internet Justice?". Global News. CanWest Global Communications.
- George Schuurman; Janelle Blackadar (2007-12-06). "Man facing six charges in Child Exploitation investigation, Photograph released, Chris Forcand, 53" (PDF). News Release. Toronto Police Service. Archived (PDF) from the original on 2008-02-27. Retrieved 2008-02-25.
- Jonathan Jenkins (2007-12-07). "Man trolled the web for girls: cops". CANOE. Toronto Sun. Retrieved 2008-02-19.
- "La suppression du site Wanted Pedo, vaine tentative de censure - donde vamos". dondevamos.canalblog.com. 2016-03-18. Retrieved 2016-10-02.
- Internet Interceptors (2017-01-01). "can paedophile hunters jeopardise case". Retrieved 2017-01-02.
- Daniel, Mac, "Vigilante Websites Combat Solicitation of Minors for Sex", Boston Globe. Oct 11, 2003. pg. B.3 
- Colgin, Chris and Jason Trahan, "Campaign against Child Sex Predators Draws Critics", Dallas Morning News. September 11, 2006