The 1880 Oxford by-election was held in May 1880 due to the incumbent Liberal MP William Vernon Harcourt becoming Home Secretary and seeking re-election to Parliament.
Harcourt had been one of the two MPs for Oxford since 1868 and had developed a reputation as a skilled debater but without tact.
In the 1880 general election he had narrowly beaten his Conservative fellow MP, Alexander William Hall.
The Liberals formed a government and Harcourt was invited to be Home Secretary which meant that he would have to resign his seat and seek re-election.
Hall fought a vigorous campaign getting endorsements from A. E. Housman and the Prime Minister's son, Sir Robert Peel.