SM U-103 was an Imperial German Navy Type U 57 U-boat that was rammed and sunk by HMT Olympic during the First World War. U-103 was built by AG Weser in Bremen, launched on 9 June 1917 and commissioned 15 July 1917. She completed five tours of duty under Kptlt. Claus Rücker and sank eight ships totalling 15,467 gross register tons (GRT) before being lost in the English Channel on 12 May 1918.