al-Qasim ibn Ubayd Allah

{{short description|Abbasid Vizier and Official (901–904)}}

{{Infobox person

| name = Al-Qasim ibn Ubayd Allah
القاسم بن عبيد الله

| image =

| image_size =

| alt =

| caption =

| other_names = {{plainlist|

• Abu'l-Husayn
• Ibn Ubayd Allah
• Wali al-Dawla (title)

}}

| father = Ubayd Allah ibn Sulayman

| mother =

| children = {{plainlist|

• Al-Husayn ibn al-Qasim
• Muhammad ibn al-Qasim}}

| birth_date =

| birth_place = Abbasid Caliphate

| death_date = October 904

| death_place = Baghdad, Abbasid Caliphate

| occupation = Abbasid vizier and official

| years_active = April 901 – October 904
(under Al-Muktafi)

}}

Abu'l-Husayn al-Qasim ibn Ubayd Allah ({{Langx|ar| أبو الحسين القاسم بن عبيد الله}}) was a senior official of the Abbasid Caliphate who served as vizier from April 901 until his own death in October 904.

Hailing from the Banu Wahb, a family of Nestorian Christian origin that had served in the caliphal bureaucracy since late Umayyad times, Ubayd Allah was the son and grandson of viziers.{{sfn|Bosworth|2002|pp=33–34}} He had served as aide to his father, Ubayd Allah ibn Sulayman, during the latter's decade-long vizierate, and then succeeded him upon his death, heading the government during the last months of the reign of al-Mu'tadid ({{reign|892|902}}) and the early years of al-Muktafi ({{reign|902|908}}). Al-Qasim largely dominated the young al-Muktafi, who awarded him with the title of Wali al-Dawla ({{langx|ar|ولي الدولة||Protector of the Dynasty}}) and gave one of his daughters to one of al-Qasim's sons.{{sfn|Bosworth|2002|p=33}}

Unlike his father, who was widely esteemed for his honesty and justice, al-Qasim was corrupt and cruel, ordering the executions of anyone that displeased him or presented a potential challenge, such as the Saffarid emir Amr ibn al-Layth, the general Badr al-Mu'tadidi, or the poet Ibn al-Rumi. The powerful finance secretary Ali ibn al-Furat was saved from a similar fate only by al-Qasim's illness and death. This death meant the end of the Banu Wahb's hold on power, which now passed to the Banu'l-Furat. Only a generation later would al-Qasim's sons al-Husayn and Muhammad also rise to become viziers.{{sfn|Bosworth|2002|p=33}}