The End of Faith: Religion, Terror, and the Future of Reason (2004) is a book written by Sam Harris, concerning organized religion, the clash between religious faith and rational thought, and the problems of tolerance towards religious fundamentalism.

Harris began writing the book in what he described as a period of "collective grief and stupefaction" following the September 11, 2001 attacks. The book comprises a wide-ranging criticism of all styles of religious belief.

The book was first published in August 2004, and it was awarded the PEN/Martha Albrand Award for First Nonfiction the following year. The paperback edition was published in October 2005. In the same month it entered the New York Times Best Seller list at number four, and remained on the list for a total of 33 weeks.