Sir Brian Souter (born 5 May 1954) is a Scottish billionaire businessman and philanthropist.
With his sister, Ann Gloag, he founded the Stagecoach Group of bus and rail operators.
He also founded the bus and coach operator Megabus, the train operating company South West Trains, his investments company Souter Holdings Ltd and the Souter Charitable Trust.
Souter has also been politically active in Scotland, and supported the Scottish National Party financially.
In 2000, when the Scottish Executive proposed to repeal Section 2A of the Local Government Act, which prevented local authorities from "promoting homosexuality", Souter started the Keep the Clause campaign to oppose their plans, spending one million pounds of his own money to organise a private referendum across Scotland.
This campaign and other controversial statements have led opponents to accuse him of homophobia.
In 2011 he was awarded a knighthood for services to transport and the voluntary sector.
The honour was criticised by Scottish Labour Party politicians and by gay rights campaigners.
In October 2019, Souter made what is possibly the biggest charitable donation from a Scot since Andrew Carnegie gave away his fortune.
His donation of £109m came on top of £98m he had already gifted to the Souter Charitable Trust which has supported 13,000 worthwhile causes over 13 years.According to The Sunday Times Rich List in 2019, Souter and his sister Ann Gloag are worth £875 million.