Fagerson and Rae have signed two-year deals while Scott and Bryce have earned themselves one-year deals with the club.
The 19-year-old Fagerson made his debut off the bench for the Warriors in their GUINNESS PRO12 clash with Treviso while Rae spent December on loan at the Italian outfit - making four appearances.
The 20-year-old has returned to Treviso for the rest of the season on loan while Bryce, brother of Warriors hooker Kevin, has made three appearances for Glasgow this season.
Scott meanwhile has represented Scotland at under-20s level but is yet to make a senior appearance for the Warriors.
And Townsend believes the deals are an important moment for the club as they look to continue the development of young talent coming through the Scotstoun academy.
"All four players have come through our academy system and have done really well this season," he said.
"It's important that we continue to develop our younger players and these three follow the likes of Finn Russell, Jonny Gray and Adam Ashe in signing professional contracts with us."
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