Apart from the very important profession of faith, the Council of Nicaea also promulgated twenty canons, most of which do not receive the same attention in research as the Nicene Creed, although these were already highly esteemed in ancient times. First of all, this chapter provides a brief review of their textual transmission. Besides the original Greek text, which has been handed down in canonical collections and writings of ecclesiastical writers, there are some translations into other ancient languages (Latin, Syriac, Coptic). Then after dividing the twenty canons into various thematic groups (for example, laws pertaining to the clergy, sacraments, ecclesiastical jurisdiction), the second part explains each canon with the aid of previous research literature and interpretations in order to provide a short overview of their purpose and content. The third part deals with the reception of the canons in the early Church by councils, bishops, and ecclesiastical writers, and asks what importance was attributed to the Nicene canons in various canonical sources. Finally, some desiderata for future research are discussed.