Saeid Aghaei (Persian: سعید آقایی; born 9 February 1995) is an Iranian professional footballer who plays as a left back (defender) for Nassaji Mazandaran in Persian Gulf Pro League.

He started his career with Gostaresh in 2012–13 Azadegan League and helped them to promote to Iran Pro League with scoring 3 times in 15 appearances.

Aghaei started 2013–14 season with Gostaresh. After a few matches, he joined Tractor to spend conscription period.

On 1 September 2020, Aghaei signed a two-year contract with Persian Gulf Pro League champions Persepolis.

He was part of Iran U–17 in 2010 AFC U-16 Championship.

He was invited by Ali Dousti Mehr to preparation for 2014 AFC U-19 Championship.

Aghaei was called up to the senior Iran squad by Carlos Queiroz for friendlies against Macedonia and Kyrgyzstan in June 2016. He made his senior debut on 4 June 2017 against Montenegro. In May 2018, he was named in Iran's preliminary squad for the 2018 World Cup in Russia but did not make the final 23.