Abbas Mirza (Persian: عباس میرزا; 26 August 1789 – 25 October 1833) was the Qajar crown prince of Iran during the reign of his father Fath-Ali Shah Qajar (r. 1797–1834). As governor of the vulnerable Azerbaijan province, he played a crucial part in the two wars against the Russian Empire (1804–1813 and 1826–1828), as well as the war of 1821–1823 against the Ottoman Empire. He is also recognized for leading Iran's first reform and modernization attempts with the help of his ministers Mirza Bozorg Qa'em-Maqam and Abol-Qasem Qa'em-Maqam.
The conflict in the Azerbaijan and Caucasus regions between Iran and the Russian Empire was prevalent throughout the time that Abbas Mirza was growing up. On March 20, 1799, he was made the crown prince and given the title of Nayeb-al-saltana (viceregent). Around the same time, he was appointed the governor of Azerbaijan, with Soleyman Khan Qajar and Mirza Bozorg Qa'em-Maqam as his adjutants. Following Russia's takeover of Ganja in 1804, Abbas Mirza was in command of the Iranian military counterattack during the first and second Russo-Iranian wars. Throughout the two wars, he fought against numerous Russian commanders in various engagements, victorious and unsuccessful alike. The Iranians ultimately lost both wars, agreeing to sign the treaties of Gulistan and Turkmenchay, in which they ceded all of their holdings in the Caucasus, corresponding to present-day Armenia, Republic of Azerbaijan, and Dagestan.