Permaisuri Siti Aishah (Jawi: ڤرمايسوري سيتي عائشه; born Siti Aishah binti Abdul Rahman; 18 November 1971) is the consort of the 11th Yang di-Pertuan Agong of Malaysia, Sultan Salahuddin Abdul Aziz Shah Al-Haj of Selangor.

She was the youngest ever Raja Permaisuri Agong (Queen) of Malaysia, ascending the throne at the age of 28 on 26 April 1999.

The second commoner to become Raja Permaisuri Agong, she is believed to have remarried since the death of her husband the late king on 21 November 2001 – a claim which she has since denied.

[1] She came back into the public eye on New Year's Day 2006 for an exclusive interview by The Star Malaysia, where the newspaper had wrongly addressed by her former title, "Tuanku Siti Aishah".

In the interview, she talked about her life since the late king (whom she fondly referred to as Almarhum) died, how she coped with his death with her family's love and support, her role as the former queen of Malaysia, her relationship with the late king, and her hope to find love and remarry again, with her parents' blessings.