Wikipedia

AllSides does not currently rate the bias of Wikipedia, despite previously rating it Center prior to March 2021. AllSides changed Wikipedia's rating to Not Rated after considering that the encyclopedia does not fit neatly into our bias rating methodologies, which were developed for news sites. Here, we detail third-party data and claims that Wikipedia has a left-wing bias. You can vote on what you think the bias of Wikipedia is above.

Table of Contents

• Third-Party Accusations of Bias
  • MRC Finds Right-Leaning Outlets Are "Effectively Blacklisted" on Wikipedia
  • Seven Studies Find Wikipedia Has Left-Wing Bias
  • DC Prosecutor Alleges Wikipedia Permits "Information Manipulation," "Propaganda"
  • Wikipedia Co-Founder Accuses Site of Bias
  • Elon Musk Calls for Wikipedia Boycott Due to Bias
  • Fox News Accuses Wikipedia of Bias on "Communism," "Socialism" Pages
• Previous AllSides Media Bias Rating for Wikipedia
• About Wikipedia

Third-Party Accusations of Bias

MRC Finds Right-Leaning Outlets Are "Effectively Blacklisted" on Wikipedia

In February 2025, Media Research Center (Right bias) analyzed how Wikipedia classifies the reliability of media sources relative to AllSides Media Bias Ratings™.

According to the report, “not a single media source listed by AllSides as ‘Lean Right’ or ‘Right’ is deemed ‘generally reliable’ by Wikipedia.” Instead, 22 of the 29 right-leaning outlets analyzed were labeled “generally unreliable,” “deprecated,” or “blacklisted,” while five others were placed in the “no consensus” category.

In contrast, 84% of the outlets AllSides rates as “Lean Left” or “Left” are classified as “generally reliable” by Wikipedia.

Seven Studies Find Wikipedia Has Left-Wing Bias

Seven studies and analyses, including 2 from Harvard researchers, show a left-wing bias at Wikipedia:

• A 2024 analysis by researcher David Rozado found that English Wikipedia contains roughly three times as many mentions of the far-right compared to the far-left.
• A 2024 analysis by researcher David Rozado that used AllSides Media Bias Ratings™ found Wikipedia associates right-of-center public figures with more negative sentiment than left-wing figures, and tends to associate left-leaning news organizations with more positive sentiment than right-leaning ones.
• One Harvard study found the articles are more left-wing than Encyclopedia Brittanica.
• Another paper from the same Harvard researchers found left-wing editors are more active and partisan on the site.
• A 2018 analysis found top-cited news outlets on Wikipedia are mainly left-wing.
• Another analysis found that pages on American politicians cite mostly left-wing outlets (AllSides Media Bias Ratings™ were used to assess this).
• American academics found conservative editors are 6 times more likely to be sanctioned in Wikipedia policy enforcement.

A a former Wikipedia editor writing for Breitbart News pointed to 5 studies that demonstrate Wikipedia's left-wing bias. One analysis used AllSides Media Bias Ratings™ to check the bias of Wikipedia sourcing. It found that "articles on American politicians tended to rely on left-wing media. Based on AllSides ratings, 33,000 sources used were left-wing with 44,000 being left-wing based on MBFC ratings. Right-wing sources were shown to be more rarely used with such sources being cited less than 10,000 times according to either rating site. Centrist sources were used more often and closer to the number of times left-wing sources were used. Neither ratings site has rated all of the outlets cited on Wikipedia, while some ratings differ between the two sites."

One 2024 analysis by Rozado found there is "the tendency in Wikipedia articles for names of prominent left-leaning politicians to be used, on average, with more positive sentiment than their right-leaning counterparts is not circumscribed to political figures. Similar associations are also apparent when examining the average sentiment with which the names of U.S. Supreme Court Justices and U.S. based journalists are used in Wikipedia articles." In addition, he found "there is a tendency in Wikipedia articles to associate left-leaning news media institutions with more positive sentiment than right-leaning news media organizations. This asymmetry however is not apparent for mentions in Wikipedia of U.S. based think tanks." This analysis used AllSides Media Bias Ratings™.
 

"The following figure shows the average sentiment with which U.S. presidents, U.S. senators, U.S. House of Representatives Congressmembers from the 117th Congress and U.S. State Governors (as of 2022) are used in Wikipedia articles. There is an average tendency in Wikipedia articles to use the names of prominent left-leaning U.S. politicians with more positive sentiment than their right-leaning counterparts."

Another analysis by Rozado found that Wikipedia is more likely to mention right-wing political extremism than left-wing political extremism.

Rozado also looked at other terms denoting extremism in Wikipedia. "The results in this case present a more nuanced picture," he wrote. "On English Wikipedia, terms using the adjective extreme to describe political extremism are more frequently associated with right-wing ideologies than with left-wing ones. Conversely, terms using the adjective radical tend to be more commonly linked to left-wing ideologies than to right-wing ones. However, it is crucial to consider the scale of the y-axes in the figures above. The terms far-right and far-left are by far the most common terms used to refer to political extremism."

A study from Harvard Business School found that Wikipedia was more left-biased the Encylopedia Brittanica. Researchers Greenstein and Zhu examined articles covering U.S. politics on Wikipedia and compared them to similar articles in Encyclopedia Britannica. They looked at word choices more consistent with left-wing and right-wing views respectively, and found articles on Wikipedia tended to show greater left-wing bias.

A subsequent study by these researchers and an additional researcher examined the bias of active Wikipedia editors; it found they tended to be more left-wing and more partisan than their right-wing counterparts. "However, the researchers also concluded many editors moderate their bias in editing the more they edit and thus over many years left-wing editors moved towards a more neutral stance somewhat more quickly," Breitbart noted in its coverage of the study. "One flaw in the study is it excludes editors who made over 950 edits in a year, which excludes many of the site’s most active partisans."

Another analysis looked at Wikipedia sourcing and found (emphasis ours) "establishment left-leaning outlets such as the and BBC News, each cited in around 200,000 articles, were often the most-cited news sources. The left-wing Guardian was the third most-cited outlet with almost 100,000 articles citing the outlet. Among the top ten outlets cited in Wikipedia articles, only one was right-leaning."

In a piece for Critic, a British magazine, American academics found that Wikipedia editors whose contributions favored the right-leaning perspective were more likely to be sanctioned in “arbitration enforcement,” cases where special site administrators can impose restrictions on editors.

DC Prosecutor Alleges Wikipedia Permits "Information Manipulation," "Propaganda"

In April 2025, Trump-appointed DC prosecutor Ed Martin penned a letter to Wikimedia Foundation, Wikipedia's parent group, alleging that it engages in the dissemination of propaganda that subverts the American public, violating its obligations under 501(c)(3), a section of the IRS code outlining conduct for charities.

"It has come to my attention that the Wikimedia Foundation, through its wholly owned subsidiary Wikipedia, is allowing foreign actors to manipulate information and spread propaganda to the American public," Martin wrote. "Wikipedia is permitting information manipulation on its platform, including the rewriting of key, historical events and biographical information of current and previous American leaders, as well as other matters implicating the national security and the interests of the United States. Masking propaganda that influences public opinion under the guise of providing informational material is antithetical to Wikimedia’s “educational” mission."

The Wikimedia Foundation, Martin said, is directed by a board “that is composed primarily of foreign nationals” who are “subverting the interests of American taxpayers.” 

"Again, educational content is directionally neutral; but information received by my Office demonstrates that Wikipedia’s informational management policies benefit foreign powers," Martin wrote.

The Free Press reported, "The letter did not specify which foreign actors were manipulating information on Wikipedia and did not cite examples of alleged propaganda. However, a person close to Martin said he is concerned about 'edits on Wikipedia as they relate to the Israel-Hamas conflict that are clearly targeted against Israel to benefit other countries.'"

Wikipedia's page on Martin labeled him with the subjective qualifier "far-right," AllSides found [retrieved April 28, 2025, 12:10pm ET].

Wikipedia Co-Founder Accuses Site of Bias

Many have accused Wikipedia of having a left-wing bias, including its co-founder Larry Sanger, who conducted his own bias analysis of the website. Wikipedia has been accusing of failing to mention the crimes of communist and socialist regimes, employing left-wing bias in its decriptions, using mostly left-wing media outlets in its sourcing, and of being more likely to sanction conservative editors.

"The days of Wikipedia's robust commitment to neutrality are long gone," co-founder Larry Sanger told Fox News in Feb. 2021. "Wikipedia's ideological and religious bias is real and troubling, particularly in a resource that continues to be treated by many as an unbiased reference work." In his bias analysis of Wikipedia, co-founder Sanger wrote:

Wikipedia’s “NPOV” is dead. The original policy long since forgotten, Wikipedia no longer has an effective neutrality policy. There is a rewritten policy, but it endorses the utterly bankrupt canard that journalists should avoid what they call “false balance.” The notion that we should avoid “false balance” is directly contradictory to the original neutrality policy. As a result, even as journalists turn to opinion and activism, Wikipedia now touts controversial points of view on politics, religion, and science.

He gives numerous examples, noting President Barack Obama’s article mentioned none of his Administration’s scandals, but scandals on President Trump’s page were extensively documented. He also wrote:

Wikipedia can be counted on to cover not just political figures, but political issues as well from a liberal-left point of view. No conservative would write, in an abortion article, “When properly done, abortion is one of the safest procedures in medicine,” a claim that is questionable on its face, considering what an invasive, psychologically distressing, and sometimes lengthy procedure it can be even when done according to modern medical practices. ... To pick another, random issue, drug legalization, dubbed drug liberalization by Wikipedia, has only a little information about any potential hazards of drug legalization policies; it mostly serves as a brief for legalization, followed by a catalog of drug policies worldwide. Or to take an up-to-the-minute issue, the LGBT adoption article includes several talking points in favor of LGBT adoption rights, but omits any arguments against.

Sanger also notes numerous instances of bias in articles on Jesus Christ, stating that "Wikipedia’s claims are tendentious if not false, and represent a point of view that many if not most Christians would rightly dispute."

Elon Musk Calls for Wikipedia Boycott Due to Bias

In Jan. 2025, Elon Musk tweeted, "Defund Wikipedia until balance is restored!" with a link to Rozado's analysis of mentions of political extremism in Wikipedia (more here.) In December 2024, X owner Elon Musk posted, "Stop donating to Wokepedia until they restore balance to their editing authority," linking to a graphic showing Wikipedia’s annual budget report from 2023—2024, which indicated it spent over $50 million of a total $177 million budget on Diversity, Equity, and Inclusion.

Fox News Accuses Wikipedia of Bias on "Socialism," "Communism" Pages

In a 2021 analysis article on Wikipedia's left-wing bias, Fox News noted, "The two main pages for "Socialism" and "Communism" span a massive 28,000 words, and yet they contain no discussion of the genocides committed by socialist and communist regimes, in which tens of millions of people were murdered and starved." Fox continues:

Wikipedia’s Socialism page announces: "The Soviet era saw some of the most significant technological achievements of the 20th century." It ignores a man-made famine in which Soviet dictator Joseph Stalin commandeered the food from regions like Ukraine and Kazakhstan, leaving millions to starve to death even as the Soviet Union exported grain to foreign countries. Asked for comment, a Wikimedia Foundation spokesperson sent a statement noting that "Wikipedia is a living, breathing project, and is always evolving just as our shared understanding of a topic does." The response also noted that the foundation does not directly control content on Wikipedia, which is written by volunteer editors. The statement did not address any specific criticisms of the content. The Wikipedia socialism page also mentions China’s Communist history, but only begins its description in 1976, after Mao Zedong’s reign of terror had already killed tens of millions. "After Mao Zedong's death in 1976... China's economic performance pulled an estimated 150 million peasants out of poverty," the encyclopedia says. The article fails to mention Mao’s prior communist programs such as his "Great Leap Forward", in which private farming was abolished, leading to mass famine that killed tens of millions. It also neglects to mention Mao’s "Cultural Revolution", in which, according to the History Channel, "Millions of young radicals who formed the paramilitary Red Guards shut down schools, destroyed religious and cultural relics and killed intellectuals and party elites believed to be anti-revolutionaries."

Fox News also said that "the two main Socialism and Capitalism [Wikipedia] pages also fail to note any of the atrocities committed by other socialist and communist regimes, from Venezuela, Cuba, Nicaragua, Cambodia, or North Korea, among others."

Previous AllSides Media Bias Rating for Wikipedia

Prior to March 2021, AllSides rated Wikipedia as Center. We changed Wikipedia to Not Rated after considering that the encyclopedia does not fit neatly into our bias rating methodology, which was developed for news sites. We became aware of the accusations of Wikipedia bias, and decided to move the website to Note Rated until we could devise a better way to rate them within our system.

About Wikipedia

Wikipedia is a multilingual, web-based, free-content encyclopedia project based on an openly editable model. The name "Wikipedia" is a portmanteau of the words wiki (a technology for creating collaborative websites, from the Hawaiian word wiki, meaning "quick") and encyclopedia. Wikipedia's articles provide links to guide the user to related pages with additional information. Wikipedia is frequently used and cited by AllSides when conducting media bias-related research. Since its launch in 2001, it has become one of the world's most-trafficked websites.

AllSides Analysis Finds Wikipedia Shows Bias Against Conservatives

A Jan. 2025 analysis by AllSides reviewers on the left, center, and right found Wikipedia pages on conservative media outlets and figures include negativity bias, subjective qualifiers, bias by placement, and reasons to doubt the credibility of the outlets and figures early on their pages.

For example, Wikipedia pages for conservative outlets The Epoch Times and Fox News contain criticism and subjective qualifying adjectives like “far-right” within the first three paragraphs. Meanwhile, the Wikipedia pages for CNN, NBC, and other outlets on the left did not feature criticisms in paragraphs one through three, but just detailed the outlets’ reach, showing bias by placement [retrieved Jan. 22, 2025].

Wikipedia also showed slant and bias by placement when it comes to right-wing figures, analysts noted. On the page for conservative commentator Tucker Carlson, paragraph three said he circulates “far-right” ideas and promotes conspiracy theories, while paragraph three on the page for left-wing commentator Rachel Maddow merely explains her scholarly credentials [retrieved Jan. 22, 2025].

An analyst in the Center noted that Wikipedia pages on figures who are Zionist or pro-Israel tend to contain fewer terms like “conspiracy theorist” or “far-right,” pointing to pages on commentators like Candace Owens and Ben Shapiro as examples (Candace has been critical of Israel, while Shapiro is supportive). Ben Shapiro's page prominently — in the first few grafs – notes all his achievements, while Owens’ page prominently (in the first few grafs) notes she's a conspiracist.

The first paragraph of conservative outlet Breitbart’s page notes critics of its content who have called it "misogynistic, xenophobic, and racist.”

The first section of conservative outlet The Washington Times’ page also contains negativity bias, arguing that The Washington Times has “published columns contradicting the scientific consensus on multiple environmental and health issues,” and includes a subjective claim that it has published "conspiracy theories.”

The Daily Caller’s page also contains similar negativity bias in paragraph 2.

Meanwhile, the first paragraphs of outlets on the left, such as Associated Press, The Atlantic, and New York Times, which have been criticized by conservatives, do not contain negativity bias nor subjective claims from critics.

Funding sources to the Wikimedia Foundation, which hosts Wikipedia, can be viewed here. As of Jan. 2024, donors included Apple Inc., Google.org, Microsoft Matching Gift Program, Adobe, Cisco, Walt Disney Company Foundation, Comcast, GE Foundation, Pfizer, Spotify, and Soros Fund Charitable Foundation Matching Gifts Program.