al-Musta'in II

{{Short description|Ruler of Taifa Zaragoza (1085–1110)}}

{{Infobox royalty

|name = Abu Ja'far Ahmad Al-Musta'in II
أبو جعفر أحمد المستعين الثاني

|image =

|alt =

|caption =

|succession = Ruler of Taifa Zaragoza

|reign = 1085–1110

|predecessor = Yusuf al-Mu'taman ibn Hud

|successor = Abd al-Malik Imad ad-Dawla

|birth_date =

|birth_place = Zaragoza

|death_date = 1110

|death_place = Zaragoza

|burial_place = Zaragoza, Spain

|full name =

|dynasty = Hud

|father =

|mother =

|religion = Sunni Islam}}

Abu Ja'far Ahmad ibn Yusuf ibn Hud ({{langx|ar|أبو جعفر أحمد بن يوسف بن هود}}), known by the regnal name al-Musta'in Billah ({{langx|ar|المستعين بالله||He who looks for help to God}}), was the fourth member of the Banu Hud family to rule the Taifa of Zaragoza. He ruled from 1085 to 1110. He was the son of Yusuf al-Mu'taman ibn Hud.

He died in the battle of Valtierra on 24 January 1110.