Mhairi Black (; born 12 September 1994) is a Scottish politician.
She has been the SNP Member of Parliament for Paisley and Renfrewshire South since 2015, when she defeated Labour's Shadow Foreign Secretary Douglas Alexander.
She was re-elected in 2017 and again in 2019.Black was the Baby of the House as the youngest member in the House of Commons of the United Kingdom from 2015 to 2019, Labour MP Nadia Whittome, who was aged 23 at the time of her election to the House of Commons, was elected at the 2019 election.
When elected in May 2015, she was 20 years and 237 days old, making her the youngest ever Member of Parliament (MP) elected to the House of Commons of the United Kingdom since at least the Reform Act of 1832, replacing William Wentworth-Fitzwilliam; who was 20 years and 11 months old when elected in 1832.