[1] Master Chief Petty Officer Affiliation UNSC Navy Higher Rank Command Master Chief Petty Officer Lower Rank Senior Chief Petty Officer Known Master Chief Petty Officers John-117
	[Source]

Master Chief Petty Officer is an E-9 rank of the UNSC Navy, and is a non-commissioned officer. It is equal in rank to Master Gunnery Sergeant in the UNSC Marine Corps, Sergeant Major in the UNSC Army, and Chief Master Sergeant in the UNSC Air Force. Master Chief Petty Officer ranks just above Senior Chief Petty Officer and just below Command Master Chief Petty Officer.

SourcesEdit

1. ↑ This is the insignia for a UNSC Master Chief Petty Officer. However, in Halo 3, the insignia for Master Chief Petty Officer of the Navy is shown to be the same as the insignia from 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 insignias.

UNSC Defense Force enlisted ranks
	E-1	E-2	E-3	E-4	E-5	E-6	E-7	E-8	E-9	Senior Enlisted Advisor
Air Force:	AB	Amn	A1C	SrA	SSgt	TSgt	MSgt	SMSgt	CMSgt - CCM	CMSAF
Army:	PV1	PV2	PFC	SPC - CPL	SGT	SSG	SFC	MSG - 1SG	SGM - CSM	SMA
Marine Corps:	Pvt	PFC	LCpl	Cpl	Sgt	SSgt	GySgt	MSgt - 1stSgt	MGySgt - SgtMaj	SgtMajMC
Navy:	CR	CA	CN	PO3	PO2	PO1	CPO	SCPO	MCPO - CMDCM - FORCM - FLTCM	MCPON