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Common military ranks in English
Navies	Armies	Air forces
Commissioned and Non-commissioned officers
Admiral of the fleet	Marshal or Field marshal	Marshal of the air force
Admiral	General	Air chief marshal
Vice admiral	Lieutenant general	Air marshal
Rear admiral	Major general	Air vice-marshal
Commodore	Brigadier or Brigadier general	Air commodore
Captain	Colonel	Group captain
Commander	Lieutenant colonel	Wing commander
Lieutenant commander	Major or Commandant	Squadron leader
Lieutenant	Captain	Flight lieutenant
Sub-lieutenant	Lieutenant or First lieutenant	Flying officer
Ensign	Second lieutenant	Pilot officer
Midshipman	Officer cadet	Flight cadet
Enlisted grades
Warrant officer or Chief petty officer	Warrant officer or Sergeant major	Warrant officer
Petty officer	Sergeant	Sergeant
Leading seaman	Corporal	Corporal
Seaman	Private	Aircraftman

Rear admiral (Australia)
The RADM insignia
Country	Australia
Service branch	Royal Australian Navy
Abbreviation	RADM
Rank	Two-star
NATO rank	O-9
Next higher rank	Vice admiral
Next lower rank	Commodore
Equivalent ranks	Major general (Army) Air vice-marshal (RAAF)

Rear admiral is a naval commissioned officer rank above that of a commodore and captain, and below that of a vice admiral. It is generally regarded as the lowest of the "admiral" ranks, which are also sometimes referred to as "flag officers" or "flag ranks". In many navies it is referred to as a two-star rank (OF-7).

It originated from the days of naval sailing squadrons and can trace its origins to the Royal Navy. Each naval squadron would be assigned an admiral as its head, who would command from the centre vessel and direct the activities of the squadron. The admiral would in turn be assisted by a vice admiral, who commanded the lead ships which would bear the brunt of a naval battle. In the rear of the naval squadron, a third admiral would command the remaining ships and, as this section of the squadron was considered to be in the least danger, the admiral in command of the rear would typically be the most junior of the squadron admirals. This has survived into the modern age, with the rank of rear admiral the most-junior of the admiralty ranks of many navies.

In some European navies (e.g., that of France), and in the Canadian Forces' French rank translations, the rank of rear admiral is known as contre-amiral. In the German Navy the rank is known as Konteradmiral, superior to the flotilla admiral (Commodore in other navies). In the Royal Netherlands Navy, this rank is known as schout-bij-nacht (lit.: supervisor during night), denoting the role junior to the squadron admiral, and fleet admiral.

The Royal Australian Navy maintains a rank of rear admiral; refer to Australian Defence Force ranks and insignia. The abbreviation is RADM.

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