Question 111: The Jafari school of Thought are all who follow the school Shi’a? And is there any who follow this school who are not Shi’a? Are Shi’ah Ithna Ash’ari, Jafari?
Answer 111: Jafri is a surname commonly associated with those who are the descendants of the 6th Imam, Ja’far al-Sadiq (as), who was a direct descendant of Imam Ali (as) and the holy Prophet Muhammad (pbuh).
The meaning of Ja’fari sect is the Twelver Shia. Imam Ali (as) is their first infallible Imam and their last Imam is Mahdi (as). There are other names for the followers of this holy sect as follows:
Imamiyyah, Ithnā‘ashariyyah and the twelver Shia. Ja’fari is also used as another name for the Twelver Shi’is. The Twelver theology, which mainly consists of five principles [as] has formed over the course of history on the basis of the teachings of the Holy Qur’an, and hadiths from the Holy Prophet Muhammad (saws) and the Twelve Imams (pbuth) especially Imam Jafar al-Sadiq (as).
So, those who follow this school of thought are called Shia.
Note: The Ithna Ashari School is not the only group that identify as Shia but it is the majority of Shia consisting of about 85% of Shia. In addition, there are a small minority of follows from the School of Ahlul Sunnah wal Jamaah (Sunni) who love the Ahlulbayt (as) but don’t follow the hadith of the 12 Imams (as) nor disassociate with their enemies.
For further information in this regard, please refer to the following answer:
Index: The differences and similarities between Shia and Sunni, answer 187.
Index: Shia answers: The Term Shia in Quran, answer 129.