SM UC-26 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 29 August 1915 and was launched on 22 June 1916. She was commissioned into the German Imperial Navy on 18 July 1916 as SM UC-26. In nine patrols UC-26 was credited with sinking 39 ships, either by torpedo or by mines laid. On 16 February 1917, SM UC-26 was rammed by the Royal Naval vessel Mona's Queen near Le Harve. The submarine was hit by the port paddlebox of the Mona's Queen, with her steel paddle floats severely damaging the submarine's bow. UC-26 was ultimately rammed and sunk by HMS Milne off Calais on 8 May 1917.