A seraglio, serail, seray or saray (from Persian: سرای, romanized: sarāy, lit. 'palace', via Turkish, Italian and French) is a castle, palace or government building which was considered to have particular administrative importance in various parts of the former Ottoman Empire.

"The Seraglio" may refer specifically to the Topkapı Palace, the residence of the former Ottoman sultans in Istanbul (known as Constantinople in English at the time of Ottoman rule). The term can also refer to other traditional Turkish palaces (every imperial prince had his own) and other grand houses built around courtyards.

The term seraglio, from Italian, has been used in English since 1581. The Italian Treccani dictionary gives two derivations:

The term may also be spelt serail, via French influence, based on the Italian term.

Since the Topkapı Palace's harem (commonly known as "The Seraglio harem") grew in prominence and fame, the term saray/serail/seraglio began also being commonly used as a synonym of harem, the sequestered living quarters used by wives and concubines in an Ottoman household.

Besides the Topkapı Palace ("The Seraglio"), the most famous seray is the Grand Serail of Beirut (Arabic: السراي الكبير, romanized: Al-Sarāy al-Kabir) in Lebanon, which is the headquarters of the prime minister. It is situated atop a hill in downtown Beirut a few blocks away from the Lebanese Parliament. The hill was the site of an Ottoman army base from the 1840s, which was built up, fortified, and expanded in the 1850s. At first it was known as al quishla, from the Turkish word kışla, meaning barracks.

Other examples include:

Seventeen saraya were established in Palestine during Ottoman rule; most were established by regional officials and their families such as the Ridwan dynasty and Zahir al-Umar and his family.