|Hierarchy of naval officer ranks|
|Admiral of the navy
Admiral of the fleet • Fleet admiral
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.
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 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.
Since the mid-1990s, the insignia of a Royal Australian Navy rear admiral is the crown of St Edward above a crossed sword and baton, above two silver stars, above the word "AUSTRALIA". Like the Royal Navy version, the sword is a traditional naval cutlass. The stars have eight points, unlike the four pointed Order of the Bath stars used by the army (which are often referred to as "pips"). Prior to 1995, the RAN shoulder board was identical to the Royal Navy shoulder board. The Royal Navy shoulder board changed again in 2001 and the Australian and UK shoulder boards are now identical except for the word "AUSTRALIA".
The first female to hold the rank of rear admiral within the Royal Australian Navy was Rear Admiral Robyn Walker, AM, RAN as the Surgeon‑General for the Australian Defence Force who was appointed on 16 December 2011.
In the Royal Canadian Navy, the rank of rear-admiral (RAdm) (contre-amiral or CAm in French) is the Navy rank equivalent to major-general of the Army and Air Force. A rear-admiral is a flag officer, the naval equivalent of a general officer. A rear-admiral is senior to a commodore and brigadier-general, and junior to a vice-admiral and lieutenant-general.
The rank insignia for a rear-admiral is two gold maple leaves beneath crossed sword and baton, all surmounted by St Edward's Crown, worn on shoulder boards and slip-ons on uniforms other than the service dress tunic. The service dress features a wide strip of gold braid around the cuff and, since June 2010, above it a narrower strip of gold braid embellished with the executive curl. On the visor of the service cap are two rows of gold oak leaves.
Indian Navy also maintains a rear admiral rank senior to commodore and captain ranks and junior to vice admiral (and admiral) ranks.
The rank insignia for a rear-admiral is two stars beneath crossed sword and baton, all surmounted by Emblem of India, worn on shoulder boards.
Islamic Republic of Iran 
The Islamic Republic of Iran Navy (IRIN), also known as the Iranian Navy.
A rear admiral in the Pakistani Navy is a senior and two-star rank naval officer, appointed in higher naval commands. Because of the command and staff experience, the rear admiral rank is superior to commodore and captain. However, the rank is junior to the three-star rank vice-admiral and four-star rank admiral, who is generally a Chief of Naval Staff of the Navy.
The Republic of Singapore Navy uses two ranks with the title of rear admiral: Rear-Admiral (one-star), a one-star rank; and Rear-Admiral (two-star), a two-star rank.
United Kingdom 
United States 
In the United States since 1984, there have been two ranks with the title of rear admiral: Rear admiral (lower half) (RDML), a one-star rank; and rear admiral (upper half) (RADM), a two-star rank. Prior to that, a combination of ranks were used – see the main article and Commodore (United States) for the history and evolution of these ranks.
In Vietnam, the equivalent to rear admiral is the chuẩn đô đốc or đề đốc, literally "master of the rowboat".