Scotland under-20 captain Jonny Gray has signed a three-year professional contract, while hookers Fraser Brown and Kevin Bryce have agreed one-year deals.
Gray, 19, has been part the Scottish Rugby Elite Development Programme this season, after joining the club last summer from Hamilton.
He said: "I'm honoured to have agreed a professional contract with the Warriors.
"I've really enjoyed working with the squad, who have all made me feel very welcome since I joined the club and I'm grateful for the experience in the PRO12 this season.
"The set up at Scotstoun is excellent and it's the perfect platform for me to develop as a player.
"Competition is tough with the talent we have here, but the players have been great and continually offer me advice, which has helped a lot. I'm really looking forward to continuing my career in Glasgow over the next three years."
Prior to joining the Warriors, the second row trained and played rugby in New Zealand, having been named as one of the recipients of the 2012 John Macphail Scholarship.
Gray was called up to the Scotland under-20 set-up at the age of just 17 and was made captain when he returned to the national age-grade squad for the 2013 RBS 6 Nations.
This season he has made two appearances off the bench for Glasgow, in the wins over Edinburgh and Newport Gwent Dragons.