Dium is a Latinisation of Greek Dion, and may refer to:

• Dion, Pieria, in modern Greece
• Dium (Chalcidice), a city of ancient Chalcidice, now on Mount Athos
• Dium (Coele-Syria), a city of ancient Coele-Syria, now in Jordan or Syria
• Dium (Crete), a city of ancient Crete, Greece
• Dium (Euboea), a town of ancient Euboea, Greece
• Dium (Pisidia), a town of ancient Pisidia, now in Turkey
• Dium (Thessaly), a town of ancient Thessaly, Greece