The Asr prayer (Arabic: صلاة العصر ṣalāt al-ʿaṣr, "afternoon prayer") is one of the five mandatory salah (Islamic prayer). As an Islamic day starts at sunset, the Asr prayer is technically the fifth prayer of the day. If counted from midnight, it is the third prayer of the day.

The Asr prayer consists of four obligatory rakat. An additional four rakat are recommended to be performed before the obligatory rakat. As with Zuhr prayer, if it is performed in congregation, the imam is silent except when announcing the takbir, i'tidal, and taslim.

The period of Asr prayer begins approximately when the sun is halfway down from noon to sunset (various branches of Islam differ on the starting point; some say that it begins when the shadow of an object equals its actual length plus its shadow during noon, others say that the actual length must be doubled). Asr prayer ends at sunset, when Maghrib prayer begins. Muslims are also allowed to perform Zuhr and Asr prayers one after another, so they may perform the Asr prayer before the actual period begins. Barring the Hanafi school, which forbids prayer combination, Sunni Muslims may only do this if they are traveling and incapable of performing the prayers separately. Amongst Sunnis, Salafis allow the combining of prayers for a wide range of reasons such as when various needs or difficulties arise (taking precedence from Hanbali and Shafiite schools).

The Asr daily prayer is mentioned as the middle prayer in the Qur'an at sura 2 (Al-Baqara) and it is emphasized on the Muslims to protect this prayer meaning that it should be performed at all costs, ayat 238. al-Asr is also the title of the 103rd chapter (sura) of the Qur’ān.

The five daily prayers collectively are one pillar of the Five Pillars of Islam, in Sunni Islam, and one of the ten Practices of the Religion (Furū al-Dīn) according to Shia Islam.