U-136 may refer to one of the following German submarines:

, a Type U 127 submarine launched in 1917 and that served in the First World War until surrendered on 23 February 1919; broken up at Cherbourg in 1921 During the First World War, Germany also had this submarine with a similar name: , a Type UB III submarine launched in 1918 , a Type VIIC submarine that served in the Second World War until sunk by on 11 July 1942