To our knowledge, representations of zodiac symbols are unattested in Egyptian rock art. The investigation of a petroglyph at the site of el-Hosh in Upper Egypt has found that it bears a strong resemblance to the zodiac sign of Capricornus, a composite figure combining the head and forequarters of a goat with the body of a fish. The sign first arose in Mesopotamia in the late third millennium BCE, from which it subsequently spread to the Mediterranean region. Following a review of the symbol’s development in Egypt, in which its occurrence on ceilings, coffins, and coins was examined, we are confident that the petroglyph depicts Capricornus and that it was most likely produced during the Graeco-Roman Period. Furthermore, as the figure is related stylistically to a nearby petroglyph of a chameleon, an equally unique subject for Egyptian rock art, the latter can now be dated more firmly to the same era.