Siddiqui, is a Muslim

Muslim

A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...

 family name, found in the South Asia

South Asia

South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...

 and the Middle East. Shaikh is an additional title used occasionally by Siddiqui/Siddique to signify their Arab

Arab

Arab people, also known as Arabs , are a panethnicity primarily living in the Arab world, which is located in Western Asia and North Africa. They are identified as such on one or more of genealogical, linguistic, or cultural grounds, with tribal affiliations, and intra-tribal relationships playing...

 heritage. People having surname "Siddiqui" claim their relationship as offspring of Abu Bakr

Abu Bakr

Abu Bakr was a senior companion and the father-in-law of the Islamic prophet Muhammad. He ruled over the Rashidun Caliphate from 632-634 CE when he became the first Muslim Caliph following Muhammad's death...

 Siddique , the first Khalifa (Caliph

Caliph

The Caliph is the head of state in a Caliphate, and the title for the ruler of the Islamic Ummah, an Islamic community ruled by the Shari'ah. It is a transcribed version of the Arabic word   which means "successor" or "representative"...

) and an early companion and friend of the Prophet

Prophet

In religion, a prophet, from the Greek word προφήτης profitis meaning "foreteller", is an individual who is claimed to have been contacted by the supernatural or the divine, and serves as an intermediary with humanity, delivering this newfound knowledge from the supernatural entity to other people...

 Muhammad.
The name "Siddiqui" derives from the word Siddiq, which means "truthful" in Arabic.