In astronomy, the geocentric model (in Greek: geo = earth and kentron = center) of the universe is the theory that the Earth is at the center of the universe and the Sun and other celestial objects go around it.

Belief in this system was common in ancient Greece. It was embraced by both Aristotle and Ptolemy, and most Greek philosophers assumed that the Sun, Moon, stars, and naked eye planets circle the Earth. Aristarchus of Samos proposed a heliocentric model of the solar system, but he was clearly in the minority in believing that the Earth was not central.