Qulay'a (Arabic: قليعة, romanized: Qulayʾa), also transliterated Qulay'at or Qleiat) is a village and medieval citadel in northwestern Syria, administratively part of the Tartus Governorate.

[1] The fortress of Qulay'a was one of the several held by the Nizari Ismaili state in the Syrian coastal mountains and is locally known as Al-Sheikh Deeb Castle (Arabic: قلعة الشيخ ديب, romanized: Qal'at Sheikh Dib).

The fortress stands at an elevation of 730 meters (2,400 ft) above sea level.

[4] During the Ottoman period, Qulay'a was the center of a minor nahiye (subdistrict) in the hill country west of Hama.

[5] Unlike many other former Crusader or Nizari Isma'ili fortresses during that period, where the inhabitants of the fortress were Sunni Muslims or Isma'ili Shia Muslims amid a largely Alawite-populated countryside, by the 17th century the inhabitants of the Qulay'a castle itself were Alawites.