Mahdi Pirjahan (Persian: مهدی پیرجهان; born 23 September 1999 in Tabriz) is an Iranian athlete specialising in the 400 metres hurdles. He represented his country at the 2019 World Championships narrowly missing the semifinals. His personal best in the event is 49.33 seconds set in Lucknow in 2019. This is the current national record.