Seven Achaemenid clans or seven Achaemenid houses were seven significant families that had key roles during the Achaemenid era. Only one of them had regnant pedigree.^[1]

According to Herodotus, after the departure of Cambyses II for Egypt, the usurper Gaumata impersonated Bardiya (Smerdis), the younger brother of Cambyses, and became king. A group of seven Persian noblemen became suspicious of the false king and conspired to overthrow Gaumata. After the death of Gaumata, in a negotiation to determine the form of government, Otanes (Hutan) recommended a democratic government but his offer was not adopted and monarchy continued in Iran.^[2]

The names of them were mentioned in Herodotus' Histories and the Behistun Inscription:

1. Otanes
2. Ardumanish (possibly the same as Aspathines)
3. Gobryas, father of Mardonius
4. Intaphrenes
5. Megabyzus I
6. Hydarnes
7. Darius I

Arthur Emanuel Christensen the Danish historian and Iranologist, Herodotus was mistaken to say their main prominence was participation of them in murder of Gaumata. Also, the Parthians continued those formations.^[3]

• Seven Parthian clans

• Sassanid Persia by Arthur Emanuel Christensen