During a meeting of the Assembly of Experts in Tehran on Tuesday, the senior cleric was re-elected as the head of the body by winning 66 votes.
Ayatollah Mahmoud Hashemi Shahroudi and Ayatollah Mohammad Ali Movahedi Kermani were also elected as the first deputy and second deputy of the Assembly with 72 and 70 votes in favor respectively.
Ayatollah Jannati will head the Assembly of Experts for another two years.
The high-ranking body elects and oversees the activities of the Leader of the Islamic Revolution.
The 88 members of the assembly are directly elected to office by people for an eight-year term. It holds biannual meetings to appoint a new chairman.
The latest Assembly of Experts polls were held across Iran on February 26, 2016.