The Principality of Koknese (Russian: Кукейносское княжество; German: Fürstentum Kokenhusen; Latin: Terra Kukonois) was a small vassal state of the Principality of Polotsk on the right bank of the Daugava River in ancient Livonia (modern Latvia) during the Middle Ages.

At the beginning of the 13th century, when the crusading Livonian Brothers of the Sword led by bishop Albert of Riga began to occupy the shores of the Gulf of Riga, the Eastern Orthodox prince Vetseke ruled the fortress of Koknese some 100 km upstream.

[1] According to old sources, Vetseke gave half of his land to Albert of Riga in 1205 in return for protection against the Duchy of Samogitia.

When the bishop left for Germany Vetseke rebelled, killed all the Germans in Koknese and called on Polotsk for support.

Archaeological excavations in Koknese showed that town in the 13th century was inhabited mainly by Latgalians and Selonians with a very small Slavic minority.