Mary Louise McDonald (born 1 May 1969) is an Irish politician who has served as Leader of the Opposition in Ireland since June 2020 and president of Sinn Féin since February 2018. She has been a Teachta Dála (TD) for the Dublin Central constituency since 2011. She previously served as vice president of Sinn Féin from 2009 to 2018 and a Member of the European Parliament (MEP) for the Dublin constituency from 2004 to 2009.