The siege of Sveaborg was a siege by Imperial Russian forces of the sea fort of Sveaborg, off the coast of Helsingfors (Helsinki); at the time Finland was part of the Kingdom of Sweden. It took place in the spring of 1808, during the Finnish War. Despite its formidable reputation as "the Gibraltar of the North", the fortress surrendered after a siege of two months. As its capitulation was followed by the rapid collapse of Swedish resistance elsewhere, and ultimately the Russian conquest of Finland, the siege is often regarded as the decisive battle of the war.

Friedrich Wilhelm Graf von Buxhoevden was a Russian general of the infantry and government official. Buxhoeveden commanded the Russian armies during the Finnish War.