Salah (Arabic: ٱلصَّلَاةُ, romanized: aṣ-Ṣalāh, also spelled Salat), also known as Namaz (Persian: نماز, romanized: namāz), is the practice of formal worship in Islam, consisting of a series of ritual prayers performed at prescribed times daily. These prayers, which consist of units known as rak'ah, include a specific set of physical postures, recitation from the Quran, and prayers from the Sunnah, and are performed while facing the direction towards the Kaaba in Mecca (qibla). The number of rak'ah varies depending on the specific prayer. Variations in practice are observed among adherents of different madhahib (schools of Islamic jurisprudence). The term salah may denote worship in general or specifically refer to the obligatory prayers performed by Muslims five times daily, or, in some traditions, three times daily.

The obligatory prayers play an integral role in the Islamic faith, and are regarded as the second and most important, after shahadah, of the Five Pillars of Islam for Sunnis, and one of the Ancillaries of the Faith for Shiites. In addition, supererogatory salah, such as Sunnah prayer and Nafl prayer, may be performed at any time, subject to certain restrictions. Wudu, an act of ritual purification, is required prior to performing salah. Prayers may be conducted individually or in congregation, with certain prayers, such as the Friday and Eid prayers, requiring a collective setting and a khutbah (sermon). Some concessions are made for Muslims who are physically unable to perform the salah in its original form, or are travelling.

In early Islam, the direction of prayer (qibla) was toward Bayt al-Maqdis in Jerusalem before being changed to face the Kaaba, believed by Muslims to be a result of a Quranic verse revelation to Muhammad.

The Arabic word salah (Arabic: صلاة, romanized: Ṣalāh, pronounced [sˤa.laːh] or Arabic pronunciation: [sˤə.ɫaːt]) means 'prayer'. The word is used primarily by English speakers to refer to the five daily obligatory prayers. Similar terms are used to refer to the prayer in Malaysia, Brunei, Indonesia, Somalia, Tanzania, and by some Swahili speakers.

The origin of the word is debated. Some have suggested that salah derives from the triliteral root و-ص-ل (w-ṣ-l) which means 'linking things together',^{[citation needed]} relating it to the obligatory prayers in the sense that one connects to Allah through prayer. In some translations, namely that of Quranist Rashad Khalifa, salah is translated as the 'contact prayer', either because of the physical contact the head makes with the ground during the prostration, or again because the prayer connects the one who performs it to Allah. Another theory suggests the word derives from the triliteral root ص-ل-و (ṣ-l-w), the meaning of which is not agreed upon.^{[full citation needed]}

In Iran and regions influenced by Persian culture – particularly the Indo-Persian and Turco-Persian traditions – such as South Asia, Central Asia, China, Russia, Turkey, the Caucasus or the Balkans, the Persian word namaz (Persian: نماز, romanized: namāz) is used to refer to salah. This word originates from the Middle Persian word for 'reverence'.

The word salah is mentioned 83 times in the Quran as a noun.

Islamic jurisprudence (fiqh) divides human actions into five categories, known as "the five rulings" (al-aḥkām al-khamsa), and acts of worship will be classified accordingly; mandatory (farḍ or wājib), recommended (mandūb or mustaḥabb), neutral (mubāḥ), reprehensible (makrūh), and forbidden (ḥarām). Salah is generally classified into obligatory or mandatory (fard) prayers and supererogatory prayers, the latter being further divided into Sunnah prayers and Nafl prayers.