SM UC-15 was a German Type UC I minelayer submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 23 November 1914, laid down on 28 January 1915, and was launched on 19 May 1915. She was commissioned into the German Imperial Navy on 28 June 1915 as SM UC-15. Mines laid by UC-15 during her eight patrols are credited with sinking 3 ships. UC-15 disappeared in November 1916.

The Type UC I coastal submarines were a class of small minelaying U-boats built in Germany during the early part of World War I. They were the first operational minelaying submarines in the world. A total of fifteen boats were built. The class is sometimes also referred to as the UC-1 class after SM UC-1, the class leader. The Italian X-class submarine was a reverse-engineered and modified type of the UC-1-class.