In May 2015, Frontiers Media removed the entire editorial boards of Frontiers in Medicine and Frontiers in Cardiovascular Medicine after editors complained that Frontiers Media staff were "interfering with editorial decisions and violating core principles of medical publishing". In total 31 editors were removed. Following this incident, Nature Publishing Group ended its collaboration with Frontiers with the intent "never to mention again that Nature Publishing Group has some kind of involvement in Frontiers".
In June 2015, Retraction Watch referred to the publisher as one with "a history of badly handled and controversial retractions and publishing decisions".
According to researchers referenced in a 2015 blog post quoted by Allison and James Kaufman in the 2018 book Pseudoscience: The Conspiracy Against Science, "Frontiers has used an in-house journals management software that does not give reviewers the option to recommend the rejection of manuscripts" and the "system is setup to make it almost impossible to reject papers". However, as of 2022, Frontiers maintains that reviewers are given the option to reject papers with specific recommendations.
In 2017, further editors were removed, allegedly for their rejection rate being high. In December 2017, Adam Marcus and Ivan Oransky of Retraction Watch wrote in the magazine Nautilus that the acceptance rate of manuscripts in Frontiers journals was reported to be near 90%.
In 2022, the editors of a special issue with the online journal Frontiers in Research Metrics and Analytics voiced their concerns about the editorial practices at Frontiers, including flaws in the peer review process, unwillingness to discuss these concerns, and forbidding the editors from writing about their concerns in the editorial of the special issue.
In January 2023, Zhejiang Gongshang University (浙江工商大学) in Hangzhou, China announced it would no longer include articles published in Hindawi, MDPI, and Frontiers journals when evaluating researcher performance.
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Also in January 2023, Inria released recommendations on "grey-zone publishers", namely Frontiers and MDPI, highlighting stark differences in editorial process between titles owned by Frontiers and other journals in the fields of Computer Science and Mathematics, and urging "extreme vigilance about the quality of articles published by Frontiers."
In 2024, a study highlighted how MDPI, Frontiers, and Hindawi journals had massively increased their publishing of special issue articles, associated with very rapid article acceptances. This has raised concerns over the quality of the Frontiers peer review process.
A 2026 study found that over 20% of papers published by Frontiers in the field of cancer research were likely the product of fraudulent research paper mills.
Inclusion in Beall's list
In October 2015, Frontiers was added to Beall's List of "Potential, possible, or probable" predatory open-access publishers. The inclusion was met with backlash among some researchers. Daniël Lakens, researcher at the Eindhoven University of Technology, said "articles people have published in Frontiers are no longer judged based on their own quality, but are now seen as less valuable because Frontiers is on Beall's list" and that "[h]aving a single influential individual cast doubt on such a huge journal feels very unfair". At the time, the Committee on Publication Ethics (COPE) said that "there have been vigorous discussions about, and some editors are uncomfortable with, the editorial processes at Frontiers" but that "the processes are declared clearly on the publisher's site and we do not believe there is any attempt to deceive either editors or authors about these processes". Frontiers was a member of COPE; the statement concluded that "we have no concerns about Frontiers being a COPE member and are happy to work with them". For transparency, COPE added that one of Frontiers' employees, Mirjam Curno, sits on COPE's council, although that employee was not involved in the statement.
In July 2016 the maintainer of Beall's List, Jeff Beall, recommended that academics not publish their work in Frontiers journals, stating "the fringe science published in Frontiers journals stigmatizes the honest research submitted and published there", and in October of that year Beall reported that reviewers have called the review process "merely for show".
In September 2016, Frontiers demanded that the university where Beall worked force him to retract his claims. Beall deleted his blacklist in January 2017. Pressure by Frontiers was reported to be a large factor in the controversial shutdown of Beall's List.
Controversial articles
In April 2013, Frontiers in Psychology retracted a controversial article linking climate change denialism and "conspiracist ideation"; the retraction was itself also controversial and led to the resignations of at least three editors.
In late September 2014, Frontiers in Public Health published a controversial article that supported HIV denialism; three days later the publisher issued a statement of concern and announced an investigation into the review process of the article. It was eventually decided that the article would not be retracted but instead was reclassified as an opinion piece. It has since been retracted.
In November 2016, a paper in Frontiers in Public Health linking vaccines to autism was provisionally-accepted, then retracted. Public criticism noted the paper relied on flawed methodology for reliable results, basing its conclusions only on an online questionnaire, filled in by 415 mothers of school children who self-reported whether their children had neurodevelopmental disorders, and their vaccination status.
In 2021, a provisionally accepted controversial paper in Frontiers in Pharmacology on COVID-19 and the use of the antiparasitic drug ivermectin was ultimately rejected by the editors as it contained "unsubstantiated claims and violated the journal's editorial policies". This drew anger from the authors of the paper, who called the move "censorship". Retraction Watch noted that this was not the first time Frontiers provisionally accepted and then rejected a controversial paper.
A study published in Frontiers in Virology in February 2022 said that Moderna had patented a 19 nucleotide genetic sequence uniquely matching a part of the SARS-CoV-2 spike protein three years prior to the pandemic, arguing it was evidence that the virus was manufactured as part of a lab leak conspiracy. The study has been widely derided for its misunderstanding of statistical likelihood, particularly as the 19 nucleotide sequence is not unique to SARS-CoV-2, and is also found in organisms like bacteria and birds. Craig Wilen, an immunobiology professor of the Yale School of Medicine, likened the study to "complete garbage" and a "conspiracy theory" rather than legitimate research.
A now-retracted 2024 paper published in Frontiers in Cell and Developmental Biology was criticized for having figures AI generated with Midjourney, described as featuring "garbled text and a wildly incorrect diagram of a rat penis". Microbiologist and scientific integrity consultant Elisabeth Bik described it as being "a sad example of how scientific journals, editors, and peer reviewers can be naive—or possibly even in the loop—in terms of accepting and publishing AI-generated crap".
