Grand Ayatollah Seyyed Hossein Kazemeyni Boroujerdi is an Iranian Muslim cleric who advocates the separation of religion and government. He first expressed his opposition to the Islamic government of Iran in 1994. He wrote to Pope Benedict XVI and the European Union to complain about the suspicious circumstances surrounding the death of his father Ayatollah Seyyed Mohammad Ali Kazemeini Boroujerdi in 2002, the subsequent confiscation of his father's mosque, and his own and his followers' harassment by Iran's theocratical government.

He opposes the theocratic concept of rule or "guardianship" by Islamic jurists. He said Iranians are "tired of the religion of politics and political slogans." The Iranians "believe that they are loyal to the fundamentals of the true religion and the Prophet's mission, but they are opposed to the politicization of religion and its exploitation by a group that has nothing to do with true Islam. Islam is the religion of tolerance, forbearance, and mercy, to the point where emphasized to us that 'there is no compulsion in religion."" Boroujerdi and many of his followers were arrested in Tehran on October 8, 2006, following a clash between police and hundreds of his followers. Iranian officials charged him with having claimed to be a representative of the hidden Imam, (a venerated figure in Shia Islam), charges he denies. According to mardaninews website, as of 1 June 2008 "judicial authorities have released no information concerning his prosecution" and his medical condition is deteriorating.