Shias are Muslims just like Catholics are Christians. Shia is a branch of Islam. The two main branches of Islam are Sunni and Shia; Sunnis constitute the vast majority of the Muslim diaspora but there are some regions where Shias are either in the majority or form a powerful minority.
Islam versus Shia comparison chart
Place of worship
Mosque/masjid, any place which is considered clean by Islamic standards.
Mosque, Imambarah or Ashurkhana, Eidgah
Use of statues and pictures
Images of God or prophets not permitted. Art takes the form of calligraphy, architecture etc. Muslims distinguish themselves from other groups by not drawing lifelike human works, which could be mistaken as idolatry. No image is representative of God
1.6 billion Muslims
Imam leads congregational prayer in a mosque. Sheikh, Maulana, Mullah and Mufti
Islam is totally opposed to monasticism and celibacy. Marriage is an act of Sunnah in Islam and is strongly recommended. Men can only marry the "people of the book" i.e., Abrahamic religions. Women can only marry a Muslim man.
Man may marry up to 4 women.
imams identified as
Shiites believe they are the successors of Ali; Sunnis regard them as their clergy.
Divinely guided. Considered as the only legitimate interpreters of the Quran.
Second coming of Jesus
Belief of God
Only one God (monotheism). God is the one True Creator. God has always existed, none existed before him and will exist forever. He transcends life and death. No part of His creation resembles Him, He cannot be seen, but sees all.
Angels are created from light and remain unseen as they worship and follow God's commands.
Angels obey God's commandments. They have limited free will, though no drive to sin.
Ramadan (month of fasting), Eid-ul Adha (feast of the sacrifice), Eid-ul Fitr (sweet festival at the end of Ramadan).
Ashura, Eid al Fitr, Eid al Adha, Eid al ghadeer
Origins of the Shia sect
Almost immediately after the death of Muhammad, there had been a split within the religion he had founded. Many of his followers believed that his son-in-law, Ali, should be his successor. Others did not. So, the followers of Ali formed their own sect called Shia. They revered him almost as much as they had revered Muhammed. Ali was eventually murdered by other Muslims who opposed his succession, and his death recalled by Shias, during the holiday of Ashura.