SM UB-77 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 2 October 1917 as SM UB-77. UB-77 was surrendered on 16 January 1919 in accordance with the requirements of the Armistice with Germany and broken up in Swansea in 1921.