Denis M. MacEoin (born 1949, Belfast, Northern Ireland) is a British analyst and writer. He was a "Senior Editor" from 2009–2010 at Middle East Quarterly, a publication of the conservative American think tank Middle East Forum, where he is also a Fellow.  A former lecturer in Islamic studies, his academic specialisations are Shi'ism, Shaykhism, Bábism, and the Bahá'í Faith. MacEoin is a pro-Israel campaigner (he first visited the country in 1968), who says he has "very negative feelings" about Islam. Since 2014 has published at the Gatestone Institute, of which he is a Senior Fellow, a number of essays on current events with a Middle Eastern focus. As a novelist, MacEoin writes under the pen names Daniel Easterman and Jonathan Aycliffe.
MacEoin studied English Language and Literature at the University of Dublin (Trinity College) and Persian, Arabic and Islamic Studies at the University of Edinburgh. He carried out research for his PhD degree at King's College, Cambridge. From 1979–80, he taught English, Islamic Civilization, and Arabic-English translation at Mohammed V University in Fez, Morocco, resigning from the University shortly after commencing employment there. MacEoin claims the resignation was due to disputes over contract changes, working environment and payment for his services as a Lecturer. In 1986, he was made Honorary Fellow in the Centre for Islamic and Middle East Studies at Durham University. He was the Royal Literary Fund Fellow, assisting with academic writing at Newcastle University from 2005–2008,
MacEoin has published extensively on Islamic topics, contributing to the Encyclopaedia of Islam, the Oxford Encyclopaedia of Islam in the Modern World, the Encyclopædia Iranica, the Penguin Handbook of Religions, journals, festschrifts, and books, and has himself written a number of academic books.
- The Sources for Early Bābī Doctrine and History. Leiden: Brill. 1992. ISBN 978-9004094628.
- Rituals in Babism and Baha'ism. UK: British Academic Press and Centre of Middle Eastern Studies, University of Cambridge. 1994. ISBN 1-85043-654-1.
- The Hijacking of British Islam. London: Policy Exchange. 2007. ISBN 978-1-906097-10-3.
- The Messiah of Shiraz: Studies in Early and Middle Babism. Leiden: Brill. 2008. ISBN 978-90-04-17035-3.
- Music, Chess and Other Sins (PDF). London: Civitas. 2009. ISBN 978-1906837068. (Report on radicalism in about 80 schools in the UK)
- Dear Gary, Why You're Wrong about Israel. US: Library of Middle Eastern Democracy. 2013. ISBN 978-0957482500.
- The Last Assassin (1984)
- The Seventh Sanctuary (1987)
- The Ninth Buddha (1988)
- Brotherhood of the Tomb (1989)
- Night of the Seventh Darkness (1991)
- The Name of the Beast (1992)
- The Judas Testament (1994)
- Day of Wrath (1995)
- The Final Judgement (1996)
- K is for Killing (1997)
- Incarnation (1998)
- The Jaguar Mask (2000)
- Midnight Comes at Noon (2001)
- Maroc (2002)
- The Sword (2007)
- Spear of Destiny (2009)
- Naomi's Room (1991)
- Whispers in the Dark (1992)
- The Vanishment (1993)
- The Matrix (1994)
- The Lost (1996)
- The Talisman (1999)
- A Shadow On the Wall (2000)
- A Garden Lost in Time (2004)
- The Silence of Ghosts (2013)
- "Biography of Denis MacEoin". Middle East Forum.
- Milne, Seumas (20 December 2007). "Cameron must rein in these neo-con attack dogs". The Guardian. London. Retrieved 22 May 2010.
- "Writings by Denis MacEoin :: Gatestone Institute". Gatestone Institute.
- "Denis MacEoin". The Fellowship Scheme. Royal Literary Fund. Retrieved 25 February 2014.
- Kazensky, Michelle, ed. (2008). The Writers Directory 2008. 2. Thomson Gale. p. 1238.