Warriors' back-row duo, John Beattie and John Barclay, lock James Eddie and centre Iain Kennedy are among 16 players in the squad connected with professional clubs.
Glasgow defence coach Gary Mercer is part of the U21 management team.
Paxton said: "We have a nucleus of players who are currently involved with pro-rugby set-ups. This will provide a strong backbone for our squad and I'm looking for them to set the tone.
"I feel that right through this squad we have players who will be very competitive. A number of them played in the world championships in Mendoza, Argentina last summer so they are aware of the intensity of this tournament. I'd expect those players to draw on their experience of that competition," he added.
Scotland have been drawn against Australia (Friday 9 June, Vichy), Italy (Tuesday 13 June, Vichy) and England (Saturday 17 June, Riom) in the pool rounds of the Championship.
Scotland U21 squad
Props: Innes Brown (Stirling County and Fife & Tayside Institute of Sport), Ryan Grant (The Army), Kyle Traynor (Edinburgh Gunners, Boroughmuir and East of Scotland Institute of Sport), David Young (Leicester Tigers)
Hookers: Sean Crombie (Aberdeen GSFP and Grampian Institute of Sport), Gregor Wood (Watsonians)
Locks: James Eddie (Glasgow Warriors and Ayr), Allan Kelly (Hillhead/Jordanhill and West Of Scotland Institute of Sport), Ian Nimmo (Leicester Tigers)
Back-row: John Barclay (Glasgow Warriors and Scottish Institute of Sport), John Beattie (Glasgow Warriors and Scottish Institute of Sport), Alan MacDonald (Edinburgh Gunners and Scottish Institute of Sport), Scott Newlands (Heriot's and East of Scotland Institute of Sport), Ross Rennie (Edinburgh Gunners, Stewart's Melville FP and East of Scotland Institute of Sport)
Scrum halves: Ciaran Beattie (Border Reivers, Selkirk and East of Scotland Institute of Sport), Greig Laidlaw (Jed-Forest)
Stand-offs: David Blair (Sale Sharks) CAPTAIN, James King (Border Reivers and Melrose)
Centres: Ben Cairns (Edinburgh Gunners, Currie and Scottish Institute of Sport), Chris Dunlop (Durham University), Iain Kennedy (Glasgow Warriors and Glasgow Hawks), Garry Law (Border Reivers and Hawick)
Back three: Ben Addison (Stirling County and Central Scotland Institute of Sport), Robert Cairns (Boroughmuir), Cameron Johnston (Newcastle Falcons and Scottish Institute of Sport), Lee Kibble (Border Reivers and Biggar)
Management: John Jeffrey (manager), Iain Paxton (head coach), Greig Oliver (backs coach), Gary Mercer (defence coach), Neil McIlroy (assistant forwards coach and video analyst), Dr Jonathon Hanson (team doctor), Kath Carswell (physiotherapist)