The Schäffer affair was a controversial diplomatic incident caused by Georg Anton Schäffer, a German who attempted to seize the Kingdom of Hawaii for the Russian Empire. While on a trading expedition to the Kingdom, the Russian-American Company (RAC) vessel Bering ran aground during a storm at Waimea on Kauai in January 1815. The chieftain of the island, Kaumualii, seized the company goods on board. Schäffer was sent later that year from Russian America to recover the lost property, where he would spend the following two years courting native allies to overthrow Kamehameha I.

A simple mission led by an inexperienced but ambitious physician unfolded into a major blunder for the Company. Kaumualii, who sought outside help in his domestic rivalry with King Kamehameha, invited Schäffer to his island and manipulated him into believing that the RAC could easily take over and colonize Hawaii. Schäffer soon planned a full-blown naval assault on the Hawaiian islands. His actions were not sanctioned by RAC governor Alexander Andreyevich Baranov, who gave no instructions beyond either regaining the lost company items or compensation for them in sandalwood.

Mounting resistance of Native Hawaiians and American traders forced Schäffer to admit defeat and leave Hawaii in July 1817, before his triumphant reports from Kauai reached the Russian court. The Company recognized a loss of no less than 200,000 rubles but continued entertaining "the Hawaiian project" until 1821. The Company then sued Schäffer for damages, but after an inconclusive legal standoff found it easier to let him go back to Germany.