Raheem J. Kassam (born 1 August 1986) is a British political activist, former editor-in-chief of Breitbart News London, and former chief adviser to former UK Independence Party (UKIP) leader Nigel Farage. He has been described as far-right and right-wing by several media publications. Kassam formerly ran in the party's November 2016 leadership election before dropping out of the race on 31 October 2016. He is the former global editor-in-chief of Human Events and most recently became the editor-in-chief of The National Pulse.

Kassam was born in the Hammersmith Hospital in White City, West London. His parents were Tanzanian Muslim immigrants of Indian origin from Hillingdon. He was raised an Ismaili Shia Muslim but wrote in 2016 that he had not been a practising Muslim for over a decade. Kassam was formerly an atheist, stating that Christopher Hitchens' rejection of religious faith ("religions are versions of the same untruth") inspired him. He now identifies as a Christian. Kassam was educated at Bishopshalt School, a state comprehensive school in Uxbridge and the independent St Helen's College, Hillingdon, and then studied politics at the University of Westminster.

Kassam briefly worked for the American financial services firm Lehman Brothers before it went bankrupt in 2008.

Kassam was a national executive board member of the youth movement Conservative Future and director of campus anti-extremism group Student Rights, and campaigned against the London School of Economics for accepting money from Gaddafi's Libya; the university's director Howard Davies would later resign when new revelations revealed the extent of the institution's relationship with the Gaddafi regime. In a 2011 interview, Kassam named his idols as Michael Gove, Margaret Thatcher and Barry Goldwater, and spoke of his admiration for the United States's free markets. He has called his former university, the University of Westminster, a "hotbed of radical Islam", citing the fact that Jihadi John was at his campus as evidence.

In 2011, Kassam was employed as campaigns director at the Henry Jackson Society, a neoconservative foreign policy think-tank.

Kassam managed electoral campaigns in the UK and US, and was Executive Editor of The Commentator blogging platform, but left the organisation after falling out with the founding editor, Robin Shepherd, who described Kassam as "a danger to British democracy, and the rule of law". He has been a member of conservative think tanks such as the Bow Group, the neoconservative Henry Jackson Society, the Gatestone Institute and the Middle East Forum, and was involved in an attempted foundation of the UK version of the Tea Party movement. Kassam was a supporter of the controversial Young Britons' Foundation, described by its founder as a "conservative madrasa" which later shut down due to allegations of misconduct against director Mark Clarke. He and James Delingpole set up the London edition of the American far-right news outlet Breitbart News. Kassam left Breitbart in May 2018.

In June 2018, Kassam helped organise and held a speech at a 10,000-people strong "Free Tommy" demonstration in London in support of counter-jihad activist Tommy Robinson.

In 2018, Kassam joined the Institut des sciences sociales, économiques et politiques (Institute of Social, Economic and Political Sciences), founded by politicians in the far-right National Front Marion Maréchal-Le Pen and Thibaut Monnier, in Lyon, France.