The St Marylebone by-election of 5 December 1963 was held after Conservative Member of Parliament (MP) Wavell Wakefield became a hereditary peer. Though there was a large swing against the government, the seat was retained for the Conservatives by Quintin Hogg, who had renounced his peerage in order to re-enter the House of Commons, in the hope of being chosen as party leader following the resignation of Harold MacMillan, and thereby becoming Prime Minister. Hogg went on to hold the seat in the 1966 and 1970 General Elections. Like his predecessor, Hogg would leave the seat on being given a life peerage.
Forty years previously, the constituency had been represented by Hogg's father, Douglas Hogg.