Mahdi Pirjahan (; 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, India, in 2019. This is the current national record. He repeated the same record in 2021 Summer World University Games held on 3 August 2023 in Chengdu, China.
Tokyo 2020 Summer Olympic Games
Pirjahan became the fourth Iranian athlete to win a quota place in Tokyo 2020 Olympics. He was supposed to participate at the Men's 400m hurdles but has tested positive for the coronavirus.