Janet Laurel Adamson (née Johnston;^[1] 9 May 1882 – 25 April 1962) was a British Labour Party politician who served as a Member of Parliament (MP) from 1938 to 1946, and as a junior minister in Clement Attlee's post-war Labour government.

Janet Laurel Johnston was born on 9 May 1882, the daughter of Thomas Johnston of Kirkcudbright. She married, in 1902, to William Murdoch Adamson, a Transport and General Workers' Union official who became Labour MP for Cannock.^[1][2]

From 1928 to 1931, Adamson was a member of London County Council for Lambeth North. She served on the National Executive Committee of the Labour Party from 1927 to 1947, which she chaired from 1935 to 1936.^[1][2]

Adamson unsuccessfully contested Dartford at the 1935 general election, when the sitting Conservative MP Frank Clarke held the seat with a significantly reduced majority.^[3] However, Clarke died in July 1938, and at the resulting by-election in November 1938, Adamson won the seat on a swing of 4.2%.^[3] With her husband, she became the only husband and wife in the House of Commons.^[4]

The constituency was divided in boundary changes for the 1945 general election, when Adamson was elected with a large majority (27% of the votes) for the new Bexley constituency.^[5] She served as a Parliamentary Private Secretary from 1940 to 1945 and Parliamentary Secretary to the Ministry of Pensions from 1945 to 1946,^[1] under minister Wilfred Paling.

Adamson resigned from Parliament in 1946, becoming Deputy Chair of the Unemployment Assistance Board from 1946 to 1953.^[1] Her resignation precipitated a by-election in July 1946 which was narrowly won by the Labour candidate Ashley Bramall.^[5] At the next general election, in 1950, the seat was won by future Prime Minister Edward Heath.

Adamson died on 25 April 1962.^[6]