Brigg was a county constituency centred on the town of Brigg in North Lincolnshire. It returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom, elected by the first-past-the-post voting system.

The 1964 United Kingdom general election was held on Thursday 15 October 1964. It resulted in the Conservatives, led by incumbent Prime Minister Alec Douglas-Home, narrowly losing to the Labour Party, led by Harold Wilson; Labour secured a parliamentary majority of four seats and ended its thirteen years in opposition since the 1951 election. Wilson became the youngest Prime Minister since Lord Rosebery in 1894. To date, this is also the most narrow majority obtained in the House of Commons, with just one seat clearing Labour for a majority government.