The roots of the practice of divination in Buddhism can be traced back to Ancient India. However, the engagements of medieval Chinese Buddhists with practices of divination did not only draw on traditions of India, but also experienced a strong influence from traditional Chinese forms of divination and the Chinese society’s great interest in various practices of divination. Such deep mutual engagements can be detected in many aspects, such as the appearance of an increasing number of “divination masters”, the translation—and sometimes the “creation” of—many Chinese Buddhist texts on divination. A thorough investigation of the relationship between medieval Chinese Buddhism and the practice of divination can contribute to a more comprehensive understanding of how Buddhism developed and why attitudes toward Buddhism changed in China, the interaction between Buddhism and medieval Chinese society, the secularization and sinicization of Buddhism, and the important roles Buddhism played in the cultural exchanges between China and India. This dissertation will explore the relationship between medieval Chinese Buddhism and the practice of divination, based mainly on primary sources such as Chinese Buddhist translated texts, Buddhist texts produced in China, secular texts from the Han to the Song Dynasty, and Dunhuang manuscripts of the late Tang and early Song periods. Besides the introduction, the dissertation consists of six chapters. The first chapter addresses how, from a doctrinal perspective, Buddhism had changed its attitudes towards the practice of divination. Early Buddhism, Sectarian Buddhism, Mahāyāna Buddhism, Hīnayāna Buddhism and Esoteric Buddhism had markedly different approaches to the practice of divination. As such, a comparison of their texts is conducted, based on the different Chinese translations of Buddhist Indic texts. These include the four Āgamas, the five Vinaya-piṭakas, the texts of the Tāmraparṇīya, and several other texts that belong to Mahāyāna and Esoteric Buddhism. While the first chapter outlines how the different forms of Buddhism had changed their attitudes toward the practice of divination, the next two chapters examine how Chinese society, especially its intellectuals and elites, viewed the amalgamation between Buddhism and the practice of divination. In Chapter Two, the life stories of the divination monks found in the three hagiographical texts, the Liang Gaoseng zhuan, the Tang Gaozeng zhuan, and the Song Gaoseng zhuan, are carefully studied. The popularization of the practice of divination among the Buddhist monastics of medieval times is explored by identifying and investigating the bibliographical entries scattered in the contemporary history books and catalogues. This chapter also studies how the Chinese translations and responses to Buddhist doctrines and the Vinaya-piṭakas, the state-religion relationship, the relationships among Buddhism, Daoism and Confucius, and the laity-monastic relationship had influenced the practice of divination in Chinese Buddhism. Chapter Three focuses on the origin of the Buddhist apocryphal literature on the practice of divination and the response of Chinese society. After meticulously comparing five such texts in terms of how they view the relationship between Buddhism and the practice of divination, the reason for the long circulation history and the subsequent inclusion of two texts (Fantian shence jing and the Zhancha shan’e yebao jing) in the established body of Buddhist scriptures becomes abundantly clear—these two texts are able to accommodate the needs of the Chinese commoners and the elites concerning Buddhism. Chapter Four, taking the practice of astrology-divination as a case study, discusses the vital role Buddhism played in the introduction of foreign types of divination to China. In the medieval period, many new terminologies and exercises emerged in the practice of Chinese astrology-divination, such as the seven luminaries, the Navagraha, and the twelve zodiac houses. An analysis of the Buddhist texts on the practice of astrology-divination reveals that the spread of Buddhism, especially the Chinese translations of Buddhist texts, explains why the practice of foreign astrology-divination could enter China. In the next two chapters, an examination of the relationship between Buddhism and the practice of divination is done based on a selection of Dunhuang Manuscripts. Chapter Five begins by introducing the special characteristics of Dunhuang and Dunhuang Buddhism, followed by how these special characteristics led to the mutual engagements between Dunhuang Buddhism and the practice of divination, and how these differed from those of central China. The focus of the sixth chapter is solely on a specific Buddhist divination practice recorded in the Dunhuang manuscripts—the four-sides-dice divination. Through a thorough comparative analysis of the 12 four-sides-dice documents, this chapter traces the origin of the practice, the historical connections among the Sanskrit, Tibetan, and Chinese four-sides-dice documents, and the process of how the practice became integrated in a Buddhist context.