Erdmonas Simonaitis (October 30, 1888, in Juschka-Spötzen (Spiečiai), Province of East Prussia – February 24, 1969, in Weinheim, West Germany) was a Prussian Lithuanian activist particularly active in the Klaipėda Region (Memel Territory) and advocating its union with Lithuania. During the staged Klaipėda Revolt of 1923, he headed the pro-Lithuanian government of the region. For his anti-German activities, he was persecuted by the Nazis during World War II. He survived the Mauthausen-Gusen and Dachau concentration camps. After the war he remained in Germany and rejoined various Lithuanian organizations. He was awarded the Order of Vytautas the Great and Order of the Lithuanian Grand Duke Gediminas.