SM UB-27 was a German Type UB II submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The U-boat was ordered on 30 April 1915 and launched on 10 February 1916. She was commissioned into the German Imperial Navy on 23 February 1916 as SM UB-27. UB-27 sank 11 ships in 17 patrols for a total of 18,091 gross register tons (GRT).