He missed inclusion for the 2014 Six Nations squad despite many believing Scotland lacked a traditional openside flanker. Following the appointment of Vern Cotter as Scotland coach, Barclay was not included in any of his Scotland squads in the first year, including Cotter's first Six Nations. However he was picked in the wider 2015 World Cup training squad and earned his first cap since 2013 in the second warm-up match against Italy in August 2015. Although omitted from the final World Cup squad, Barclay was once again included in the Scotland squad for the 2016 Six Nations Championship and started the first four games at blindside flanker, scoring a try in the win over Italy.