Wikipedia
Rizvi or Rizavi is the Urdu pronunciation for the Persian surname Razavi or the Arabic surname Radawi/Radhawi. It is a surname commonly associated with Shia Muslims who are the descendants of the 8th Shiite Imam and a descendant and successor of Prophet Mohammad through his daughter Fatimah married with Ali ibn Abi talib, Imam Mohammad al-Taqi al Jawwad. Since the Rizvi clan trace their lineage to Fatimah al Zehra, they often use the prefix Syed (or its synonyms) in front of their name. Rizvi Sayyids are from the lineage of Musa al Mubarraqa the younger son of ninth Twelver Shiite Imam Mohammad al-Taqi al Jawwad and the younger brother of tenth Shiite Imam Ali al-Hadi Naqi. Musa al Mubarraqa is known to be the ancestor of those Sayyids who use the title of his grandfather and eight Shiite Imam Ali al-Reza or Al-Rida in their surnames. All Rizvi, Ridawi and Razavi Sayyids are from the descendants of Musa al Mubarraqa along with all Taqvi, Taqwi, Jawadi and Jawwadi Sayyids.
It is a fact that all Sayyids known as Razavi, Ridawi or Rizvi are actually Taqawi and Jawwadi. Imam Ali al-Reza or Al-Rida had no son other than Imam Mohammad al-Taqi al Jawwad. If he had other sons than Imam Mohammad al-Taqi al Jawwad then their offspring should have been called Razavi, Ridawi or Rizvi Sayyids. As Imam Ali al-Reza or Al-Rida came to Iran and died in Tous, many descendants of his son Imam Mohammad al-Taqi al Jawwad were also called Razavis, Ridawis or Rizvis. Many Shia Rizivis lived in the Iranian (Persian) city of Sabzevar, city of Qom and Jajarm now in North Khurasan before migrating to Delhi, Zaidpur of district Barabanki, Uttar Pradesh and Kashmir in India. Though they are often regarded as a Shia majority, there are some well known and authenticated Rizvis who prescribe to Sunni beliefs. The claim that Sunni Rizvis are descendants of Prophet Mohammad through his seventh descendant Ali ar-Ridha is true, and also holds validity for Shia Muslims.
There are well known Rizvis in the Meerut district in Uttar Pradesh, India. Although they are a Sunni majority, there are established Shias living there as well. They are the descendents of Meer Shahrukh Rizvi, a migrant from Mazendran, Iran, and close associates of Muhammad Ghori. Meer Shahrukh's tomb is in the village of Ruhasa, where he had originally settled. Meer Surkh Rizvi had 45 villages under his control, as referred to in the "Imperial Gazetteer of India, vol 16, p.157 & Vol 20, page 128(URL given below). The members of this clan were talukdars of this area. Most of them have been of the numberdar surname. Some are well respected farmers with an established status in their local communities. The younger generation has attained higher education and settled in various Indian cities and provinces. An increasing number has migrated to the West and have been working in the Gulf and other countries.