Petty Officer Third Class is the fourth enlisted rank (E-4) of the UNSC Navy and the lowest rank of non-commissioned officer, or NCO. Directly above it is Petty Officer Second Class and directly below is Crewman. It is equal to the rank of Corporal in the UNSC Marine Corps, Corporal and Specialist in the UNSC Army, and Senior Airman in the UNSC Air Force.

In informal settings, a Petty Officer Third Class is typically called a "Petty Officer."

In the UNSC Navy, enlisted personnel are referred to by their rating and rate (rank).


  1. This is the insignia for a US Navy Petty Officer Third Class. However, in Halo 3 the insignia for Master Chief Petty Officer is shown to be the same as for the US (with the standard "crow" changed for that of the UNSC "crow"). It is inferred that this applies to all UNSC Navy Enlisted rank insignes.

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