Abdallah ibn Ubaydallah ibn al-Abbas al-Hashimi () was a ninth century Abbasid personage and governor of the Yemen.
A minor member of the Abbasid dynasty, being a second cousin of the caliphs al-Hadi (r. 785âÂÂ786) and Harun al-Rashid (r. 789âÂÂ809), Abdallah was appointed governor of the Yemen by al-Ma'mun (r. 813âÂÂ833), and he arrived in Sana'a in ca. 832. He remained governor until the death of al-Ma'mun in 833, at which point he decided to place Abbad ibn al-Ghamr al-Shihabi in charge of the province and departed for Iraq.
Abdallah was also a frequent leader of the pilgrimage, having led the annual events of 828, 829, 831, and possibly 832.