For many people, spiritual practice is associated with one or another theistic religion. But this association is not inevitable. Both in the ancient and the modern worlds, teachers of certain wisdom-traditions offered techniques of spiritual development that did not require belief in God or gods. In this chapter, I discuss the practices of 11 such traditions: 5 from India (Advaita Vedanta, Samkhya, Yoga, Jainism, and Buddhism), 2 from China (Confucianism and Daoism), and 4 from Greece (Cynicism, Epicureanism, Stoicism, and Scepticism). These traditions differ from one another in many respects, but all (1) are grounded in philosophies or worldviews in which the gods are absent or subordinate, (2) advocate nondevotional spiritual practices, and (3) offer a conception of the wise man or Sage. In contrast with practitioners of theistic religions, who often engage in sectarian conflict and violence, practitioners of nontheistic traditions tend to be concerned with individual development and thus avoid sectarian violence.