Ayatollah Ahmad Jannati (born 23 February 1927) is an Iranian politician and cleric who has served as the secretary of the Guardian Council since 1992. He previously served as the fifth chairman of the Assembly of Experts from 2016 to 2024. A Principlist, Jannati has strong conservative views, such as his anti-LGBTQ rhetoric and opposition to secularism.

Jannati has been a member of the Guardian Council since 1980 and has been its chair since 1992. In 2016, he became the chairman of the Assembly of Experts, the body in charge of appointing the Supreme Leader. He was reappointed to the earlier post in 2022 and in 2023 he was re-appointed to the post of chairman of the Guardian Council.

During a Friday Prayer on 4 August 2006, Jannati asserted that "support for Hezbollah" was "a duty." Regarding Iraq, around the time its draft constitution was presented to parliament in 2005, he said: "Fortunately, after years of effort and expectations in Iraq, an Islamic state has come to power and the constitution has been established on the basis of Islamic precepts".^{[better source needed]}

In a Friday prayer sermon on 29 January 2010 in Tehran, Jannati praised Iranian judicial authorities for executing two political dissidents the day before and urged officials to continue executing dissidents until opposition protests end.

Jannati sees leniency with the dissidents as un-Islamic.

"God ordered the prophet Muhammad to brutally slay hypocrites and ill-intentioned people who stuck to their convictions. Koran insistently orders such deaths. May God not forgive anyone showing leniency toward the corrupt on Earth."

Responding to clerics such as Jannati wanting to speed up executions, Iran's judiciary chief firmly stated his opposition, commenting that it was against the Sharia and Iranian law:

"Political assumptions should not influence judicial investigations because we won't have a response before God should an innocent person be punished due to hasty action."