Are all Arabs Muslim?

No, not all Arabs are Muslim, and not all Muslims are Arab. Most Arabs are Muslim, but there are also millions of Arab Christians and smaller communities of other faiths. Meanwhile Arabs are only a minority of the world's Muslims. Most Muslims live in Asia and Africa, and the country with the most Muslims is Indonesia.

Arab is not the same as Muslim

"Arab" describes an ethnic and linguistic identity, mainly people who speak Arabic as a mother tongue and share Arab culture. "Muslim" describes someone who follows Islam. The two overlap a lot, but they are different things, like "Italian" and "Catholic".

Arabs of other faiths

Arab Christian communities have lived in the Middle East since before Islam and are still present in places such as Egypt, Lebanon, Syria, Palestine, Jordan and Iraq. There are also Arab Jews and followers of other faiths, as well as Arabs who are not religious. Before Islam, many Arab tribes were Christian, Jewish or followed other beliefs, and some of this diversity continues today. Arabic-speaking Christians even use "Allah" as the Arabic word for God.

Most Muslims are not Arab

Commonly cited estimates, such as those from Pew Research, put Arabs at roughly one in five of the world's Muslims. The largest Muslim populations are in countries such as Indonesia, Pakistan, India and Bangladesh. Large communities also live in Nigeria, Turkey, Iran, Ethiopia and across Europe and the Americas. You can check up-to-date figures from a trusted demographic source, since numbers change.

The Quran itself speaks to all humanity and counts different languages and colours among Allah's signs:

وَمِنْ ءَايَـٰتِهِۦ خَلْقُ ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضِ وَٱخْتِلَـٰفُ أَلْسِنَتِكُمْ وَأَلْوَٰنِكُمْ ۚ إِنَّ فِى ذَٰلِكَ لَـَٔايَـٰتٍ لِّلْعَـٰلِمِينَ "And one of His signs is the creation of the heavens and the earth, and the diversity of your languages and colours. Surely in this are signs for those of sound knowledge." Quran 30:22

Why the mix-up happens

Islam began in Arabia, the Quran is in Arabic and prayers are recited in Arabic.
Media coverage often shows only the Middle East when talking about Muslims.
Some Arab customs are mistaken for Islamic rules.

In reality, Islam has always been multi-ethnic. Companions of the Prophet ﷺ included Bilal from Ethiopia, Salman from Persia and Suhayb from the Roman lands. Arabic is the language of worship, but being Muslim does not require being Arab or even speaking Arabic well. See Is Islam only for Arabs?

Why it matters

Treating "Arab" and "Muslim" as the same can lead to stereotypes about both groups. It also leaves converts feeling that they must adopt Arab culture, which Islam does not ask. The Quran says that the most noble person before Allah is the most righteous, not the one from a particular people (Quran 49:13). See Do I have to give up my culture to become Muslim? and What does Islam say about racism?

Key points

Not every Arab is Muslim; Arab Christians and others have lived there for centuries.
Arabs are roughly one in five of the world's Muslims by commonly cited estimates.
Indonesia has the most Muslims of any country.
Islam is for every people, and you do not need to become Arab to be Muslim.

Tip: When you meet someone from the Middle East, don't assume their religion. Ask politely, or let them tell you.