Billah (Arabic: بالله ) is an Arabic phrase meaning with God or through God. It is used within various standard sayings such as the Hawqala and the Ta'awwudh. It is also used within personal names and titles, particularly by Caliphs and other rulers, when it might be seen as a counterpart of the Christian usage by the grace of God. It is used for example as follows:
- al-Aziz Billah (Arabic: العزيز بالله ), mighty through God
- Abu Mansoor Nizar al-Aziz Billah (955–996), fifth Caliph of the Fatimids
- Baqi Billah (Arabic: باقى بالله ), everlasting through God
- Khwaja Baqi Billah (1563–1603), Sufi saint from Kabul
- al-Mahdi Billah (Arabic: بالله المهدي), rightly guided through God
- Ubayd Allah al-Mahdi Billah (ruled 909-934), founder of the Fatimid dynasty
- Al-Muhtadi Billah (Arabic: المهتدي بالله ), rightly guided through God
- Al-Muhtadee Billah (born 1974), heir to the Sultan of Brunei
- Al-Muktafi Billah (Arabic: المكتفي بالله ), contented through God
- one of the names of Mahmud of Terengganu (born 1930), Sultan of Terengganu
- one of the names of Mizan Zainal Abidin of Terengganu (born 1962), Yang di-Pertuan Agong of Malaysia
- Al-Musta'in Billah (Arabic: المستعين بالله ), one who asks for help through God
- Al-Musta'in (Cairo), (c. 1390-1430), Abbasid "shadow" caliph
- al-Mustansir Billah (Arabic: بالله المستنصر ), one who asks for help through God
- Ma'ad al-Mustansir Billah (1029–1094), Fatimid Caliph
- Al-Musta'sim Billah (Arabic: المستعصم بالله ), he who holds fast though God
- Al-Musta'sim Billah, (1213–1258), last Abbasid Caliph in Baghdad
- Mutasim Billah (Arabic: معتصم بالله ), abstaining from sin through God
- one of the titles of Abu Bakar of Pahang (1904–1974), Sultna of Pahang, Malaysia
- Middle name of Mutassim Gaddafi, son of Libyan leader Muammar Gaddafi
- Motasim Billah Mazhabi (born 1964), Afghan politician
- al-Mutazz Billah (Arabic: المعتز بالله ), powerful through God
- Moataz Billah al Mqearhi (born 1984), Libyan footballer
- Al-Qahir Billah (Arabic: القاهر بالله), victorious through God
- Al-Qahir bi'llah (899-950), Abbasid Caliph in Baghdad