William Stuart Lancaster, known as Stuart Lancaster (born 9 October 1969) is a rugby union coach. He was the head coach of the English national rugby union team from 2011 until he stepped down on 11 November 2015, following the failure to qualify for the Quarter Finals of the Rugby World Cup. On 5 September 2016 it was announced that Lancaster would join the backroom team of Irish provincial side, Leinster Rugby. After a highly successful spell with Leinster, the club announced on 26 September 2022 that he would be leaving to join French Top14 side Racing 92 for the following season.