Lutsk Castle (Ukrainian: Луцький замок, romanized: Lutskyi zamok;, Polish: Zamek w Łucku), also locally known as Liubart's Castle (Lithuanian: Liubarto pilis, Замок Любарта, Zamok Liubarta) or Upper Castle (Lithuanian: Lucko aukštutinė pilis, Верхній замок, Verkhnii zamok), began its life in the mid-14th century as the fortified seat of Gediminas' son Liubartas (Lubart), the last ruler of united Galicia-Volhynia.

The Kievan Rus' town of Luchesk had a wooden wall as early as 1075, when Boleslaus the Bold laid siege to it for six months.

It repelled sieges by numerous potentates, including Casimir the Great (1349), Jogaila (1431), and Sigismund Kęstutaitis (1436).

It was there that the Lutsk Conference of 1429 took place, attended by Emperor Sigismund, Vasily II of Moscow, Jogaila, Vytautas the Great, and the voivode of Wallachia.

Three main towers, now named "Lubart", "Švitrigaila" (both after Lithuanian princes) and the "Bishop", were built up in the course of the 16th and 17th centuries.