The U-101 class was a class of nine submarines or U-boats planned for the Austro-Hungarian Navy () during World War I. The class was based on the Type 1916 S 1 design from Ungarische Unterseebotsbau AG. The first three boats were laid down in late 1917 and early 1918 by Austriawerft in Trieste, but none were launched or completed before the end of the war. None of the other six submarines was ever laid down.