An Imperial Army is an army of any empire. However, only some empires in history and in fiction have actually referred to their armies as "The Imperial Army".

Former Imperial Armies

In Asia

The Imperial Japanese Army

The Imperial Chinese Army

The Manchukuo Imperial Army

The Imperial Korean Army

The Imperial Iranian Army

In Europe

The Imperial Roman army

The Byzantine army

The Ottoman Army

The Army of the Holy Roman Empire (until 1806)

The Army of the Holy Roman Emperor (until 1806)

The Imperial German Army (1871–1918)

The Imperial Austrian Army (1806–1867)

The Austro-Hungarian Army (1804–1918)

The Imperial Russian Army (1721–1917)

The French Imperial Army (1804–1814 and 1815)

The Swedish Imperial Army (1611–1721)

Elsewhere

The Imperial Brazilian Army

Fictional

The Imperial Army (Star Wars) of the fictional Galactic Empire in Star Wars

The Imperial Army of the Archadian Empire in the video game Final Fantasy XII

The Imperial Army of the Imperium of Man in Warhammer 40000