Al-Qasim al-Ma'mun

{{short description|Ruler of Córdoba (r. 1018–1021, 1023)}}

{{Infobox royalty

|name = Al-Qasim al-Ma'mun
القاسم المأمون

|image =

|succession = 7th Caliph of Córdoba
(first period)

|birth_date =

|death_date =

|issue = Ali ibn Hammud

|issue-type = Brother

|reign = 1018 – 1021

|predecessor = Abd al-Rahman IV

|successor = Yahya ibn Ali

|succession1 = (second period)

|reign1 = 1023

|predecessor1 = Yahia ibn Ali

|successor1 = Abd al-Rahman V

|full name = Al-Qasim al-Ma'mun ibn Hammud
({{langx|ar| القاسم المأمون بن حمود}})

|mother =

|dynasty = Hammudid

| religion = Zaīdī Shī'a Islam

}}

Al-Qasim al-Ma'mun ibn Hammud ({{langx|ar|القاسم المأمون بن حمّود}}, died 1036) was an Arab Caliph of Córdoba in Muslim Spain for two periods, 1018 to 1021, and again for a short time in 1023 until he was driven from the city.{{Cite book |last=Dozy |first=Reinhart Pieter Anne |url=https://books.google.com/books?id=u2FBAAAAcAAJ&pg=PA332 |title=Histoire des musulmans d'Espagne: jusqu'à la conquête de l'Andalousie par les Almoravides (711 - 1110) |date=1861 |publisher=Brill |pages=332–333 |language=fr}} He was the brother of the deposed Ali ibn Hammud al-Nasir.{{Cite book |last=Guichard |first=Pierre |url=https://books.google.com/books?id=lj0Mr9hLP-oC |title=L'Espagne et la Sicile musulmanes aux XIe et XIIe siècles |date=2000 |publisher=Presses Universitaires Lyon |isbn=978-2-7297-0658-6 |pages=229 |language=fr}} His reign was described in Ibn al-Khatib's A'mal al-a'lam.

This was during a short period when the caliphate was held by the Hammudid dynasty.