In Greek mythology, Olganos (Ancient Greek: Greek, Ancient (to 1453);: Ὄλγανος) was a river and river-god, son of Beres in ancient Macedonia.
Olganos was the first son of Beres and the brother of Mieza and Beroia after whom the Macedonian cities of Mieza (now Naousa) and Beroia (now Veria) were named.
An inscribed bust of Olganos (circa. 2nd century) was found at Kopanos / Emathia and is now on display at the Archaeological Museum in Veria, Greece.