The Persian Cossack Brigade, also known as the Iranian Cossack Brigade, was a Cossack-style cavalry unit formed in 1879 in Persia. It was modelled after the Caucasian Cossack regiments of the Imperial Russian Army. Until 1920, it was commanded by Russian officers, while its rank and file were composed of ethnic Caucasians and later on Persians as well. During much of the brigade's history it was the most functional and effective military unit of the Qajar dynasty. Acting on occasion as kingmakers, this force played a pivotal role in modern Iranian history during the Persian Constitutional Revolution, the rise of Reza Shah, and the foundation of the Pahlavi dynasty.

The Pahlavi dynasty is an Iranian royal dynasty that ruled for almost 54 years between 1925 and 1979. The dynasty was founded by Reza Shah Pahlavi, a non-aristocratic Mazanderani soldier in modern times, who took on the name of the Pahlavi language spoken in the pre-Islamic Sasanian Empire to strengthen his nationalist credentials.