Ilūkste (pronunciationⓘ; Lithuanian: Alūksta, Ilūkšta; German: Illuxt) is a town in Augšdaugava Municipality in the Selonia region of Latvia.

As a settlement Ilūkste started to grow in the beginning of the 16th century when it was part of the Livonian Confederation and was administered by the Komtur of Daugavpils.

Ilūkste was first mentioned in written sources in 1559 as a small village, part of the estate lands of Count Kasper Sieberg.

After the Duchy of Courland was incorporated in the Russian Empire in 1795, thanks to its strategic location at the crossroads of Lithuania, Belarus and Daugavpils, Ilūkste became an important trade city and regional center.

In 1927 a new school building was constructed in town and Latvian poet, playwright and at that moment Minister of Education Rainis participated in the opening ceremony.