Grand Ayatollah Hussein-Ali Montazeri was an Iranian Shia Islamic theologian, Islamic democracy advocate, writer and human rights activist. He was one of the leaders of the Iranian Revolution and one of the highest-ranking authorities in Shīʿite Islam. He was once the designated successor to the revolution's Supreme Leader, Ayatollah Khomeini, but they had a falling-out in 1989 over government policies that Montazeri claimed infringed on people's freedom and denied them their rights, especially after the 1988 mass execution of political prisoners. Montazeri spent his later years in Qom and remained politically influential in Iran, but was placed in house arrest in 1997 for questioning "the unaccountable rule exercised by the supreme leader", Ali Khamenei, who succeeded Khomeini in his stead. He was known as the most knowledgeable senior Islamic scholar in Iran and a grand marja of Shia Islam. Ayatollah Montazeri was said to be one of Khamenei's teachers.

The supreme leader of Iran ), also referred to as supreme leader of the Islamic Revolution, but officially called the Supreme Leadership Authority, is the head of state and the highest political and religious authority of the Islamic Republic of Iran. The armed forces, judiciary, state television, and other key government organizations such as the Guardian Council and Expediency Discernment Council are subject to the Supreme Leader. According to the constitution, the Supreme Leader delineates the general policies of the Islamic Republic, supervising the legislature, the judiciary, and the executive branches. The current lifetime officeholder, Seyyed Ali Hosseini Khameneh known as Ali Khamenei, has issued decrees and made the final decisions on the economy, the environment, foreign policy, education, national planning, and other aspects of governance in Iran. Khamenei also makes the final decisions on the amount of transparency in elections, and has dismissed and reinstated presidential cabinet appointees. The Supreme Leader is legally considered "inviolable", with Iranians being routinely punished severely for questioning or insulting him.