Catherine Margaret Mary Maxwell Stuart, 21st Lady of Traquair (born 16 November 1964) is a Scottish landowner, politician, hotelier, brewer, and writer. She is the first female Laird of Traquair and, at the time she succeeded her father in 1990, she was the only female laird in Scotland. She took over the management of the lairdship from her mother in 1999, which includes a bed and breakfast and ancient brewery. A lifelong socialist, Maxwell Stuart ran for public office four times as a Labour Party candidate, including in the 2003 Scottish Parliament election and the 2007 Scottish Parliament election.