The adhan ([ʔaˈðaːn], Arabic: أَذَان, romanized: ʔaḏān) is the Islamic call to prayer, usually recited by a muezzin, traditionally from the minaret of a mosque, shortly before each of the five obligatory daily prayers. The adhan is also the first phrase said in the ear of a newborn baby, and often the first thing recited in a new home.

It is the first call summoning Muslims to enter the mosque for obligatory (fard) prayers (salawat); a second call, known as the iqama, summons those already in the mosque to assemble for prayer. Muslims are encouraged to stop their activities and respond to the adhan by performing prescribed prayers, demonstrating reverence for the call to prayer and commitment to their faith.

The five prayer times are known in Arabic as fajr (فجر), dhuhr (ظهر), asr (عصر), maghrib (مغرب), and isha (عشاء). In Turkey, they are called sabah, öğle, ikindi, akşam, and yatsı; the five calls to prayer are sung in different makams, corresponding to the time of day.

Adhān, Arabic for 'announcement', from the root adhina, meaning 'to listen, to hear, be informed about', is variously transliterated in different cultures.

It is commonly written as athan, or adhane (in French), azan in Iran and parts of South Asia (in Persian, Dari, Pashto, Hindi, Bengali, Urdu, and Punjabi), adzan in Southeast Asia (Indonesian and Malaysian), and ezan in Turkish, Bosnian and Serbo-Croatian Latin (езан in Serbo-Croatian Cyrillic and Bulgarian, ezani in Albanian). Muslims in many parts of South Asia, including the Malabar Coast of India and the Punjab region of India and Pakistan, use the Persian term بانگ, bāng, for the call to public prayer.

Another derivative of the word adhān is ʾudhun (أُذُن), meaning 'ear'.

The muezzin (Arabic: مُؤَذِّن muʾaḏḏin) is the person who recites the adhan from the mosque. Typically in modern times, this is done using a microphone: a recitation that is consequently broadcast to the speakers usually mounted on the higher part of the mosque's minarets, thus calling those nearby to prayer. However, in many mosques, the message can also be recorded. This is due to the fact that the "call to prayer" has to be done loudly and at least five times a day. This is usually done by replaying previously recorded "call to prayer" without the presence of a muezzin. This way, the mosque operator has the ability to edit or mix the message and adjust the volume of the message while also not having to hire a full-time muezzin or in case of the absence of a muezzin. This is why in many Muslim countries, the sound of the prayer call can be exactly identical between one mosque and another, as well as between one Salah hour and another, as is the case for the London Central Mosque. In the event of a religious holidays like Eid al-Fitr, for example in Indonesia, where the Kalimah (speech) has to be recited out loud all day long, mosque operators use this recording method to create a looping recital of the Kalimah. ^{[citation needed]} Where no adhan can be heard, then it is recommended that practitioners recite it before they begin their prayers.

The muezzin is chosen for his ability in reciting the adhan clearly, melodically, and loudly enough for all people to hear. This is one of the important duties in the mosque, as his companions and community rely on him in his call for Muslims to come to pray in congregation. The Imam leads the prayer five times a day. The first muezzin in Islam was Bilal ibn Rabah, a freed slave of Abyssinian heritage. According to Mawsuʿah al-Fiqhiyah, the muezzin should have an elegant voice too, and should be wise about the times of prayer and Islam.