Dorotheus of Sidon was a Greek astrologer of the 1st century CE. His epithet indicates an origin in the Phoenician city of Sidon. No further biographical details are recorded. His floruit followed the foundational work of Hellenistic astrologers, during a period of systematic composition and translation of astrological texts.

His major work is the Carmen Astrologicum, also known as the Pentateuch, a didactic poem on astrology in five books. The original Greek version is lost. The work survives primarily in later Arabic translations and adaptations, as well as in Greek fragments and quotations.

Dorotheus is a significant figure in the history of astrology. His Carmen Astrologicum was a highly influential textbook that systematically treated branches of natal astrology. The work forms a crucial link between Hellenistic traditions and later Persian, Arabic, and medieval Latin scholarship. Its translation into Arabic in the 8th century and later into Latin ensured its impact on astrological practice for over a millennium.