Six of the squad return to under-20 action having experienced the IRB Junior World Championships in Japan last season.
John said: "It's a real help to have these experienced players involved. Obviously the 6 Nations is a different environment to the Junior World Championship but any experience within the intense under-20 competitive environment will stand these players in good stead for the campaign and help them lead the other players.
"The Six Nations is every bit as tough as the IRB Junior World Championships and is a fantastic experience for the players who have grown up with the tournament, and will have likely been inspired to play rugby by the competition itself. It's a fantastic environment to prepare Scotland's top young players for the professional game."
Notable inclusions are Oliver Grove, the brother of recent Scotland cap success, Alex Grove, and Michael Tait, son of former Scotland and Lions centre, Alan Tait.
SCOTLAND UNDER-20 SQUAD: Forwards: Craig Owenson (Heriot's), Nicky Little (Hawick), Nick Fraser (Boroughmuir), George Hunter (Glasgow Hawks), Colin Philips (Stewart's Melville), Alun Walker (Currie), Lindsey Gibson (Melrose), Calum Taylor (Glasgow Hawks), Robert Harley (West of Scotland), Grant Gilchrist (Stirling County), Aaron Hall (Newcastle Falcons), Matthew Reid (Heriot's), David Denton (Edinburgh Accies), Michael Maltman (Heriot's), Stuart McInally (Watsonians), Calum Stidston-Nott (London Scottish), Michael Fedo (Watsonians), Chris Thomson (Loughborough University) Backs: Kris Hamilton (Caithness), Alex Black (Leeds Carnegie), Alex Blair (Edinburgh Accies), Matthew Scott (Currie), Ross Aitken (Howe of Fife), Alex Dunbar (Selkirk), Jonny Kennedy (Sale Sharks), Michael Tait (Newcastle Falcons), George Watkins (Bristol Rugby), Tom Brown (Edinburgh Accies), Oliver Grove (Worcester Warriors), Callum McBurnie (Moseley), Dougie Fife (Currie), James Johnstone (Currie)