U-145 may refer to one of the following German submarines:
, a Type U 142 submarine laid down during the First World War but unfinished at the end of the war; broken up incomplete 1919–20 During the First World War, Germany also had this submarine with a similar name: , a Type UB III submarine launched in 1918 and surrendered on 27 March 1919; hulk dumped in the Medway in 1922 , a Type IID submarine that served in the Second World War; taken to Loch Ryan on 30 June 1945; sunk on 21 December 1945 as a part of Operation Deadlight