Marshal of the air force or marshal of the air is a five-star rank (or NATO equivalent OF-10) and an English-language term for the most senior rank in some air forces. It is usually the direct equivalent of a general of the air force in other air forces, a field marshal or general of the army in many armies, or a naval admiral of the fleet.
The rank originated in the British Royal Air Force (RAF), in which the most senior rank remains Marshal of the RAF. Several other Commonwealth air forces and others that have been influenced by the practices of the RAF (especially in the Middle East) have similar names for the most senior rank, such as Marshal of the Royal Australian Air Force (RAAF). There is sometimes confusion with the next most senior ranks in such cases: air chief marshal and air marshal (proper). The rank of Marshal of the RAF existed on paper from 1919; the first person to hold the rank was Lord Hugh Trenchard, from 1927. In the UK the rank has often been held by the most senior, actively-serving RAF officer, whereas in other Commonwealth countries the equivalent rank has been purely ceremonial or honorary in function. (For example, the rank of Marshal of the RAAF has been held only by a monarch or consort.)
In Portuguese the equivalent air force ranks are Marechal do Ar (lit. "Marshal of the Air") in Brazil, or Marechal in Portugal, both of which are sometimes translated as "marshal of the air force". In the past, a similar name has been used for the most senior rank in Italian air forces.
A holder of several senior ranks in the Indonesian air force (Tentara Nasional Indonesia-Angkatan Udara; TNI-AU), may be referred to as a marsekal di TNI-AU (lit. "marshal of the TNI-AU"). The most senior rank is Marsekal Besar ("Grand Marshal") is sometimes translated as "marshal of the air force".
In Nazi Germany, the most senior rank of the Luftwaffe was Generalfeldmarschall (a rank that was also used by the German Army). While the commander of the Luftwaffe, Hermann Göring was the only person to hold the more senior rank of Reichsmarschall, this rank could technically have been bestowed on any senior officer of the Heer (army), Kriegsmarine (navy) and Luftwaffe, which together comprised the Wehrmacht.
While the air forces of the former Soviet Union had ranks named chief marshal of the aviation branch (or "chief marshal of the air force") and marshal of the aviation branch (or "marshal of the air force"), these were four-star and three-star ranks, respectively (and therefore equivalent to the less senior RAF ranks of Air Chief Marshal and Air Marshal respectively).