Principality of Tver (Russian: Тверское княжество) was a Russian principality or duchy, which existed between the 13th and the 15th centuries. It was one of the states established after the decay of the Kievan Rus', and in the 13th century Tver rivaled the Principality of Moscow and aimed to become the center of the united Russian state. Eventually it lost, decayed, and in 1485 was annexed by the Grand Duchy of Moscow. The principality was located approximately in the area currently occupied by Tver Oblast and the eastern part of Smolensk Oblast of Russia. The capital of the principality was Tver.

In the 1230s or the 1240s, Yaroslav Vsevolodovich, the Grand Prince of Vladimir, detached the city of Tver from Principality of Pereyaslavl-Zalessky where it previously belonged and gave it to his son Alexander Nevsky. In 1246, another son of Yaroslav, Yaroslav of Tver, became the Prince of Tver, and the principality was ruled by his descendants until 1485, when it was abolished. In 1264, Yaroslav was appointed the Grand Prince of Vladimir, which at the time meant he was the supreme authority of all north-western Russia. In the 13th century, Principality of Tver was less dependent from the Golden Horde than other Russian principalities were, and its population grew up. The combination of these two factors led to the rivalry between Tver and Moscow, each of which were trying to become the most influential Russian principality.

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