The Kingdom of the Cults, first published in 1965, is a reference book of the Christian countercult movement in the United States, written by Baptist minister and counter-cultist Walter Ralston Martin.

In contrast with some standard secular definitions of the word,[3] Martin narrowly defines a cult in theological terms as "a group of people gathered about a specific person—or person's misinterpretation of the Bible," while admitting that in spite of "distorting Scripture" such groups' beliefs may contain "considerable truths" that have biblical support but have become de-emphasized by mainstream Christianity, such as divine healing and prophecy.

[1] By 1989, The Kingdom of the Cults had sold over 500,000 copies and was one of the ten best-selling American spiritual books.

The book has been described as being regarded by evangelicals as "the authoritative reference work on major cult systems for nearly 40 years.

[7] After Martin's death, a revised and expanded edition was issued that listed Ravi K. Zacharias as "general editor.