Ahmad al-Muhajir (Arabic: أحمد المهاجر, Aḥmad al-muhāǧir, Arabic pronunciation: [ɑhmɑd ɑl muhɑːdʒiɽ]; 260-345 AH or c. 873-956 CE)[1] also known as al-Imām Aḥmad ibn ʿĪsā was an Imam Mujtahid and the progenitor of Ba 'Alawi sada group which is instrumental in spreading Islam to India, Southeast Asia and Africa.

Al-Imam Aḥmad ibn Isa is called al-Muhâjir (emigrant) because he left Basra, Iraq during the Abbasid Caliphate that was headquartered in Baghdad in the year 317H (929 CE).

Imam al-Muhâjir arrived in Hadhramaut at a time when an offshoot of the Kharijite sect called Ibadiyyah held political power and had widespread influence throughout the valley.

Some other ulama such as Imam ʻAbd al-Raḥman ibn ʻUbayd Allah al-Saqqāf, Habib Ṣalih al-Ḥamid, and Sayyid ʻAbd Allah ibn Ṭāhir al-Ḥaddād (brother of Habib Alwi bin Thahir al-Haddad, Mufti of Johor) and some others contend that he was a Shi'a Zaydi follower.

The Habibs from the family of Ba 'Alawi sada of Yemen fused their descent to Aḥmad al-Muhâjir through his grandson, Alawi "Sahib al-Sumal" ibn Ubayd Allah.

A recent finding of the manuscript of Imam Tirmidhi written in around 589 H, hence a contemporary book debunking the deniers' claim, mentioned a person named Muhammad Sahib Mirbath from Ba'alawi family.

[13][14] A Genealogy scholar in 8th Hijri, Bahaudin Al-Janadi in his book, "As-Suluk Fi Tabaqatil Ulama Wal Muluk"[15] said: Among them (Bait Abi Alawi) is Hasan bin Muhammad bin Ali Ba 'Alawi (who belongs to the Alawi lineage), he is a jurist who memorizes outside the head of the Al-Wajiz book is imam Ghazali" (volume 2, page 463).The Ba'alawi in Indonesia claimed some of the Nine Saints of Java or Wali Sanga in Indonesia in some traditions to be descendants of him as well.

Habib Umar bin Hafiz from Yemen was listed at number 1 in The 500 Most Influential Muslims for 2024,[19] an annual ranking compiled by Georgetown University's Prince Al-Waleed Center for Muslim–Christian Understanding and the Royal Islamic Strategic Studies Centre of Jordan.