Martin Spangberg or Martyn Petrovich Shpanberg (Мартын Петрович Шпанберг) was a Danish-Russian naval lieutenant in Russian service who took part with his compatriot Vitus Bering in both Kamchatka expeditions as second in command. He is best known for finding a sea route to Japan and exploring the Kuril Islands (one of which, Shikotan, was renamed Shpanberg by the Russians in 1796).