Isobel Lindsay (born 1943) is a former sociology lecturer, known as a Scottish nationalist and peace activist.
Born in Hamilton, Lindsay studied at Hamilton Academy and at the University of Glasgow, then was based at Strathclyde University, initially as a research fellow, then later as a lecturer in sociology. In 1960, she was a signatory to the Committee of 100 anti-war group, and through the group, she met and married Tom McAlpine.
Lindsay joined the Scottish National Party (SNP) at an early age and first stood for the Westminster parliament (unsuccessfully) in Motherwell at the 1970 general election, and became a member of the party's National Executive the same year. She was first elected as a Vice Chair of the party in 1972, initially with responsibility for publicity, then later served as Vice Chair for policy.
She stood again at the Berwick and East Lothian by-election, 1978. This was controversial, as the Berwick and East Lothian branch of the SNP had already selected a candidate for the 1979 general election. Although party policy stated that prospective parliamentary candidates were not guaranteed selection for by-elections, he initially refused to stand aside, and Lindsay only agreed reluctantly to stand, amid several resignations from the local branch. Lindsay took only 8.8% of the vote, and lost her deposit.
Although strongly associated with the left-wing of the SNP, Lindsay did not join the 79 Group. She remained on the SNP's executive until 1989, when she resigned from the party, as the sole executive member to support the party participating in the Scottish Constitutional Convention. She became the final convenor of the Campaign for a Scottish Assembly before this ambition was achieved. In 1994, she joined the Labour Party, and attempted to stand for the party at the Scottish Parliament election, 1999, but she was not approved by the party leadership.