A wilayah (Arabic: وَلاية, romanized: walāya or wilāya, plural wilāyat, wilayat; Urdu, Pashto and Persian: ولایت, romanized: velâyat, welāyat; Turkish: vilayet) is an administrative division, usually translated as "state", "province" or occasionally as "governorate". The word comes from the Arabic root "w-l-y", "to govern": a wāli—"governor"—governs a wālāya (or wilāya), "that which is governed". Under the Caliphate, the term referred to any constituent near-sovereign state.

In Arabic, wilayah is used to refer to the states of the United States, and the United States of America as a whole is called al-Wilāyāt al-Muttaḥidah al-Amrīkīyah, literally meaning "the American United States".

For Morocco, which is divided into provinces and wilāyas, the translation "province" would cause the distinction to cease. For Sudan, the term state and for Mauritania, the term region is used.

The governorates of Iraq (muhafazah) are sometimes translated as provinces, in contrast to official Iraqi documents and the general use for other Arab countries. This conflicts somehow with the general translation for muhafazah (governorate) and wilāyah (province).

In the ethnically diverse Xinjiang region of Northwest China, the seven undifferentiated prefectures proper (Chinese: 地区; pinyin: dìqū; that is, not prefecture-level cities, autonomous prefectures, etc.) are translated into the Uygur language as Vilayiti (ۋىلايىتى). For the other, more numerous types of administrative divisions in Xinjiang, however, Uygur uses Russian loanwords like oblasti or rayoni, in common with other Xinjiang languages like Kazakh.

In Kenya and Tanzania, the term wilaya is a Swahili term which refers to the administrative districts into which provinces are divided.

In Malay (both in Malaysian and Indonesian standards) and Tausug, wilayah or wilāya is a general word meaning "territory", "area" or "region".

In Thailand, it is the standard Malay term used to translate a "province"".