Previously, Army Day was celebrated on February 21 (Esfand 3) to commemorate the 1921 Persian coup d'état during the Qajar era.

[2] The holiday was moved to December 12 (Azar 28) in 1946 by Mohammad Reza Pahlavi as it was the date when the Imperial Iranian Army defeated the Soviet-backed Azerbaijan People's Government.

[2] On April 8, 1979, two months after the fall of the Shah, Khomeini met with Iranian Armed Forces soldiers who made an invaluable contribution to the victory of the revolution.

The Iranian government makes a show of military force on Iran Army Day with parades every 18 April, often demonstrating new defense technologies.

[3][4] Army veterans, active servicemen and reservists, also take part in the annually held parade.