The Varieties of Religious Experience: A Study in Human Nature is a book by Harvard University psychologist and philosopher William James. It comprises his edited Gifford Lectures on natural theology, which were delivered at the University of Edinburgh, Scotland between 1901 and 1902. The lectures concerned the psychological study of individual private religious experiences and mysticism, and used a range of examples to identify commonalities in religious experiences across traditions.

Soon after its publication, Varieties entered the Western canon of psychology and philosophy and has remained in print for over a century.

James later developed his philosophy of pragmatism. There are many overlapping ideas in Varieties and his 1907 book Pragmatism.[2]