Lieutenant-Colonel Sir John Norton-Griffiths, 1st Baronet, KCB, DSO (13 July 1871 – 27 September 1930) was an engineer, British Army officer during the Second Boer War and the First World War, and a Member of Parliament. A colourful figure in his day, known as "Empire Jack" or "Hellfire Jack", he was also the grandfather of Jeremy Thorpe, a leading British politician.