British & Irish Lions and Scotland international Grant, 28, has made 78 appearances since his 2010 move from Edinburgh and said: “I’ve really enjoyed my four years at the club and I’m excited about the opportunity I have in Glasgow. There has been so much progress at the club recently, with our support getting bigger each year and our excellent facilities at Scotstoun and a really good squad.”
Scotland A international Reid joined in 2011 from Ayr and hopes the extension can let him continue to progress.
“I’ve really improved since turning professional and joining the club and I want to continue to learn and develop my game,” the 26-year-old said.
Head coach Gregor Townsend said. “Ryan has worked hard over the past two seasons and he’s got his rewards through playing at the highest level.
“He delivers what we expect from our props, which is scrum dominance, strong defence, work-rate and accuracy in contact. His display against the Ospreys last season was one of the best individual performances of the season.”
Townsend added: “Gordon has really developed since he became a professional.”