Ahl-i-Sunnat wal Jam'at, also known as Sunni Muslim, form the vast majority. Most of them follow the jurisprudence of Imam Ahmad bin Hanbal RA. Many follow the Hanbali preacher Abd el-Wahhab and are called Wahhabis.
In addition to the Sunni Muslims, there are small communities of Twelver Shiites in northeast Saudi Arabia, Kuwait, and they form the majority in Bahrain. There are large communities of Zaydi Shiites in northern Yemen and there are large communities of Ibadi Muslims (a third sect that is not Sunni or Shiite) in Oman.
Not only in the Arabian peninsula but also in the whole world most Muslims are Sunni.
People of Arabian Peninsula were not monotheist before the emergence of Islam. They were worshiping idols as partners to Allah (or God in English).
Arabian Peninsula ____________________________________________________________ Islam began by beginning of universe creation as Allah (or God in English and same God in Christianity and Judaism) created all creatures on basis of submission and surrender to His will (that means Islam). However, Islam per Quran revelation to prophet Muhammad (peace be upon him) began in Arabian Peninsula. Refer to related question below.
Arabian Peninsula
polytheist
polytheist
islam
The Arabian peninsula.
Most Arabians practice Sunni Islam, but there are significant minorities of Ibadi Muslims (in Oman -- where they are the majority) and Zaydi Shiite Muslims (in Yemen). Most of the Arabs in Saudi Arabia identify strongly with the Wahhabist Strain of Sunni Islam.
In the Arabian Peninsula to the South West of Asia.
The Arabian peninsular.
Arabian Peninsula (Saudi Arabia)