· An introduction to Medieval Islamic Philosophy, Cambridge University Press, 1985
· Death and Loss: Compassionate Attitudes in the Classroom, Cassell, 1995
· Evil and Suffering in Jewish Philosophy, Cambridge University Press, 1995
· History of Islamic Philosophy, ed. S.H. Nasr & O. Leaman, Routledge, 1996
· Friendship East and West – Philosophical Perspectives, ed. O. Leaman, Curzon, 1996.
· History of Jewish Philosophy, ed. D. Frank & O. Leaman, Routledge, 1996
· Moses Maimonides, Curzon, 1997, 2nd Edition
· Averroes and his Philosophy, Curzon, 1997, 2nd Edition
· The Future of Philosophy: Towards the 21st Century, ed. O. Leaman, Routledge, 1998
· Key Concepts in Eastern Philosophy, Routledge, 1999
· A Brief Introduction to Islamic Philosophy, Polity Press, 1999
· Eastern Philosophy: Key Readings, Routledge, 2000
· The Jewish Philosophy Reader, ed. D. Frank, O. Leaman & C. Manekin, Routledge, 2000
· Encyclopedia of Asian Philosophy, ed. O. Leaman, Routledge, 2001
· Companion Encyclopedia of Middle Eastern and North African Film, ed. O. Leaman, Routledge, 2001
· Encyclopedia of Death and Dying, ed. G. Howarth & O. Leaman, Routledge,2001
· Introduction to Classical Islamic Philosophy, Cambridge University Press, 2001
· Cambridge Companion to Medieval Jewish Philosophy, ed. D. Frank & O. Leaman, Cambridge University Press, 2003.
· Lost in Translation: Essays in Islamic and Jewish Philosophy, Buybook, 2004
· Islamic Aesthetics: An Introduction, Edinburgh University Press, 2004
· The Qur'an: An Encyclopedia, ed. O. Leaman, Routledge, 2006
· Islamic Philosophy A-Z, with Peter Groff, Edinburgh University Press, 2007
· Controversies in Contemporary Islam, Routledge, 2013
· Biographical Encyclopedia of Islamic Philosophy, ed. O. Leaman, Bloomsbury, 2015
· The Qur'an: A Philosophical Guide, Bloomsbury, 2016
· Islam and Morality: A Philosophical Introduction, Bloomsbury, 2019
· Routledge Handbook of Jewish Ritual and Practice, ed. O. Leaman, Routledge, 2022
· Routledge Handbook of Islamic Ritual and Practice, ed. O. Leaman, Routledge, 2022