The Hermetica are a collection of ancient philosophical and religious texts, not by a single author but composed by multiple unknown writers. They were written in Greek, primarily in Roman Egypt between the late 1st and 3rd centuries CE. The authors wrote under the name of the legendary sage Hermes Trismegistus, a figure combining the Greek god Hermes and the Egyptian god Thoth, to give their ideas the authority of ancient divine revelation. According to modern scholars, the writers were likely Greek-speaking intellectuals or priests working in a milieu where Greek philosophy blended with Egyptian religious ideas.

The corpus is traditionally divided into two types. The "philosophical" Hermetica, such as the treatises in the Corpus Hermeticum, focus on theology, cosmology, and the knowledge of God for spiritual salvation. The most famous of these is the Poimandres. The "technical" Hermetica consist of works on astrology, alchemy, and magic, though this division is largely a modern construct. Significant texts also include the Asclepius, preserved in Latin, and fragments quoted by later anthologists.

The historical importance of the Hermetica lies in their role as a major strand of esoteric thought in late antiquity. They blend Platonic and Stoic ideas with a focus on spiritual knowledge, or gnosis. Although they were largely forgotten in the medieval period, their rediscovery in the 15th century had a profound impact. Renaissance thinkers believed these texts contained a pristine ancient wisdom that supported Christian thought, influencing Renaissance humanism, philosophy, and the early development of modern esotericism and science.