In 2025, all it takes to answer any factual question, no matter how trivial — Who won the 1974 World Series? Where was Taylor Swift born? — is a quick Google search and, usually, a click to Wikipedia, which has 62 million pages in English alone. But a new report from the Anti-Defamation League urges people to think twice before using the popular free encyclopedia, arguing its administrators have failed to prevent biased editors from manipulating entries related to Israel and Judaism. 

Wikipedia is maintained by an army of volunteer editors, many of whom have spent years amassing knowledge of the site’s wonky rules in order to keep its pages up-to-date and accurate. But that honor system is vulnerable to bias. The ADL found that a group of 30 editors collaborated to insert anti-Israel and antisemitic narratives and falsehoods into articles, working together in a way that may have violated Wikipedia’s policies.

“Despite Wikipedia’s efforts to ensure neutrality and impartiality, malicious editors frequently introduce biased or misleading information, which persists across hundreds if not more entries,” the report stated.

For instance, the main Wikipedia entry on Hamas was edited to downplay the Palestinian group’s terrorist activity. A subhead that was formerly ‘violence and terrorism’ is now just ‘violence’ — a change that was made on Oct. 19, 2023. ADL researchers found that the first reference of Hamas as a terrorist organization was pushed further down in the lead section, and the description of the Oct. 7 attack no longer mentions the total number of people who were killed during the massacres. Numerous other details about the attacks were also removed.

In the section titled, ‘The 2018-2019 Gaza border protests,’ an editor removed a reference to a 2018 NPR interview with a Palestinian in Gaza who was preparing to launch an incendiary balloon with a swastika on it.

A series of edit wars on Wikipedia’s main Zionism page has, since 2022, sought “to reframe Israel’s founding,” according to the report. After one editor changed the language used to describe the goal of Zionism and the Zionist movement, the editor put a 12-month discussion moratorium in place, which keeps other editors from making edits to the language.

The report issued recommendations toward policymakers, toward private companies that rely on Wikipedia’s information and toward Wikipedia itself, with the gist of its suggestions amounting to a plea to those actors to take antisemitism seriously. 

An ADL spokesperson declined to say whether the leadership of Wikipedia has been willing to engage with the group. A spokesperson for the Wikimedia Foundation, the nonprofit that operates Wikipedia, said on Monday that the organization was “not asked to provide context that might have helped allay some of the concerns raised.”

“Though our preliminary review of this report finds troubling and flawed conclusions that are not supported by the Anti-Defamation League’s data, we are currently undertaking a more thorough and detailed analysis,” the spokesperson said.

After the Oct. 7, 2023, Hamas terror attacks, Wikipedia — like social media and other platforms where Internet users go to access information — became a proxy fight for the Israeli-Palestinian conflict, and digital battles emerged over how its story is told to news consumers. 

A group of Wikipedia editors voted last summer to rate the ADL as an unreliable source on matters related to the Israeli-Palestinian conflict and antisemitism, which brought concerns about reliability and editorial integrity at the world’s largest encyclopedia to the public eye. 

In the aftermath, the ADL tried to raise the issue with leaders at the Wikimedia Foundation. Wikimedia, which has for years taken a hands-off approach to content moderation, was not responsive to concerns from Jewish advocates. More than 40 Jewish organizations wrote to Wikimedia last June urging reform. 

The problem has not receded, according to the new ADL report. If anything, it has become more entrenched. The biased anti-Israel editors — described by the ADL as “bad faith editors” — are much more active than the average editor on Wikipedia, even more so than those who edit other controversial topics. 

These “bad faith editors” attacked other editors deemed hostile to their cause in Wikipedia discussion forums, and they often used “Zionist” as a slur to tar their opponents. They would make edits on other pages, on unrelated content, to avoid detection.

On pages dedicated to major historical events, like several Israel-Arab wars or peace negotiations, editors would make “extensive edits” in “tone, content and perspective” to advance an anti-Israel narrative, the report found.

“The larger pattern of changes demonstrates a systematic effort to skew numerous Wikipedia entries to promote a set of narratives critical of Israel, often delegitimizing Israel’s existence and actions,” the report stated. Wikipedia has a policy against advocacy, and the ADL argued that this pattern of edits violates that policy. The advocacy group’s key recommendation for Wikipedia is for the encyclopedia to enforce higher content standards and stronger moderation guardrails, although such a request is likely an impossible bar to clear, given Wikimedia’s leniency toward its editors.

“The values of Wikipedia and the Wikimedia Foundation reflect our commitment to integrity and accuracy, and we categorically condemn antisemitism and all forms of hate,” the Wikimedia Foundation spokesperson said. “Content added to the site must be presented, as far as possible, without editorial bias.”

“As we have shared previously, Wikipedia is a constantly evolving, living encyclopedia based on principles of neutrality, which means content added to the site must be presented, as far as possible, without editorial bias,” they added. “Wikipedia includes more than 65 million articles and is edited by nearly 260,000 volunteers from across the world.” 

The ADL seemed to identify only limited opportunities for government officials to impact the state of affairs at Wikipedia. Policymakers “should prioritize raising additional awareness of antisemitism, and structural issues, within Wikipedia,” the ADL argued, writing that they should use their convening power to bring together academics, computer scientists, civic leaders and Wikipedians to study the issue further. 

Search engines and the large language models being used to train artificial intelligence programs should limit their use of Wikipedia, the ADL argued — and in particular, they should try to avoid citing Wikipedia as a source, instead directing users to more reputable sources. Users should be warned that Wikipedia is an unreliable source. 

A spokesperson for the ADL maintained that the report is not meant to be a repudiation of how Wikipedia currently operates. Rather, it is intended to be a very public reminder to Wikipedia “to apply its policies at scale, to prevent malicious manipulation.” 

“We are not advocating for the abandonment of Wikipedia,” said Daniel Kelley, the interim head of the ADL’s Center for Technology and Security. “We want Wikipedia to address these issues, but we would urge people to use caution with contentious articles.” 

Jewish Insider’s Tamara Zieve contributed to this report.