HMS K11 was a K class submarine built by Armstrong Whitworth, Newcastle upon Tyne. K11 was laid down in October 1915, and commissioned in February 1917. In 1917, K11 was damaged by fire during a North Sea patrol. She was forced to surface and was towed by a destroyer. K11 was part of the disastrous Battle of May Island exercise. She was forced to take avoiding action to avoid K14, but survived the exercise. K11 was sold on the 4 November 1921.