J.R. Majewski (born John Russell Majewski on November 11, 1979) is an American far-right political activist and former Republican candidate for the U.S. House of Representatives in Ohio's 9th congressional district. A native of Ohio, he served in the United States Air Force from 1999 to 2005, including a deployment to Qatar in support of Operation Enduring Freedom. After his military service, he worked in logistics and supply chain management for Owens-Illinois, a glass manufacturing company based in Perrysburg, Ohio, where he rose to a supervisory role. Majewski has been vocal in his support for former President Donald Trump and has been associated with QAnon conspiracy theories, promoting them on social media and at rallies. His political activism includes participation in far-right events and criticism of mainstream Republican figures, positioning himself as a staunch Trump loyalist.

In 2022, Majewski won the Republican primary for Ohio's 9th district but lost the general election to incumbent Democrat Marcy Kaptur by a wide margin, amid controversies over his embrace of election denialism and QAnon rhetoric. He has faced accusations of exaggerating his military service and promoting divisive conspiracy theories, including claims about the 2020 election being stolen. Majewski's campaign was marked by endorsements from Trump and far-right figures, but it also drew criticism for inflammatory statements on social issues. Following his defeat, he has continued far-right activism, including podcasting and social media engagement, and announced another run for the same seat in 2024, though he withdrew amid party pressure and internal GOP conflicts.

Majewski's public persona is deeply tied to Trump-era politics, with allegations of involvement in networks promoting misinformation and extremism. He has been criticized by both Democrats and some Republicans for his associations with QAnon and for statements deemed racist or conspiratorial, such as promoting the 'great replacement' theory. Despite these controversies, he maintains a following among hardline conservatives in northwest Ohio, leveraging his veteran status and blue-collar background to appeal to working-class voters.