Nemesius of Emesa was a Christian bishop who lived in the late 4th or early 5th century CE. He served in the city of Emesa, modern Homs in Syria, during a period of intense theological development in the late Roman Empire. Very little is known about the specific events of his life. The date of his activity is estimated based on the philosophical sources he used and the authors who later quoted his work.

He is known for a single surviving treatise titled On the Nature of Man. This work is a comprehensive study of human nature that deliberately combines Christian theology with Greek philosophy and science. Nemesius drew upon a wide range of sources, including the medical theories of Galen and the philosophies of Plato, Aristotle, and later Neoplatonists.

According to modern scholars, Nemesius holds a significant place in intellectual history for creating one of the first systematic works of Christian anthropology. His synthesis provided a philosophical and scientific framework for understanding the soul, the mind, and the human body within a Christian context. The treatise was highly influential for centuries. It was widely read in the Byzantine world and, after being translated into Latin in the Middle Ages, became an important source for major Western scholastic thinkers like Albert the Great and Thomas Aquinas.