The 1938 City of London by-election was a by-election held on 6 April 1938 for the British House of Commons constituency of City of London, which covered the "Square Mile" which was the United Kingdom's traditional financial district.
The by-election was caused by the death of one of the City's two Conservative Party Members of Parliament (MPs) Thomas Vansittart Bowater, who had held the seat since a by-election in 1924, having contested the seat in an earlier by-election in 1922.
The Conservative candidate, Sir George Broadbridge, who had been Lord Mayor of London in 1936, was returned unopposed.