The young Chelsea star, who has high expectations, will participate in Euro 2020.
Gilmour is one of three players on Scotland's 26-man squad who has never played for his country's national team. Celtic's David Turnbull and Rangers' Nathan Patterson are the other players to make their debut for Scotland.
Celtic winger James Forrest, who has been sidelined for a long time with an injury, has finally been named in Scotland, but team-mate Leigh Griffiths has been ruled out.
Alongside of Gilmour , 10 other Premier League players will play for Scotland. Most notables are Andy Robertson, Kieran Tierney, Stuart Armstrong, and Scott McTominay.
Scotland are in Group D and will face Croatia, the Czech Republic and England. They are also one of 11 countries hosting the Euro competition.
Scotland Squad for Euro2020
: Craig Gordon (Hearts), David Marshall (Derby County), Jon McLaughlin (Rangers); Liam Cooper (Leeds United), Declan Gallagher (Motherwell), Grant Hanley (Norwich City), Jack Hendry (Celtic), Scott McKenna (Nottingham Forrest), Stephen O'Donnell (Motherwell), Nathan Patterson (Rangers), Andy Robertson (Liverpool), Greg Taylor (Celtic), Kieran Tierney (Arsenal); Stuart Armstrong (Southampton), Ryan Christie (Celtic), John Fleck (Sheffield United), Billy Gilmour (Chelsea), John McGinn (Aston Villa), Callum McGregor (Celtic), Scott McTominay (Manchester United), David Turnbull (Celtic); Che Adams (Southampton), Lyndon Dykes (QPR), James Forrest (Celtic), Ryan Fraser (Newcastle United), Kevin Nisbet (Hibernian).