The new deal means the second-row be staying with the Scotstoun side until at least May 2017.
The Glasgow side have already signed up Mark Bennett, Finn Russell and Alex Dunbar in recent weeks.
Swinson joined Glasgow from Newcastle Falcons at the start of last season.
The 26-year-old has racked up 33 appearances for the club and made his Scotland debut against the Springboks on the 2013 tour to South Africa.
He has gone on to win three caps for his country and is in the Scotland squad for the upcoming RBS 6 Nations.
Tim Swinson said: “I am really happy to have agreed this new deal with the club.
“My game has really developed since I came up to Scotland last season and I’m now playing for my country, so it was an easy decision for me to stay.
“I’m ambitious and I want to win trophies and I believe we are building a squad capable of doing that.
“This has been a fantastic move for me and I’m looking forward to the next three years in Glasgow.”
Glasgow Warriors head coach Gregor Townsend said: “It’s great news for us as a club that we’ve got a long-term commitment from a quality player, who works hard to get better every day.
“I’m sure there were a few clubs in Europe interested in signing Tim, so we’re delighted that he’s decided to stay in Glasgow.
“In the 18 months he’s been at the club he’s really improved as a player and that’s down to his hard work.
“He’s got that great mix you love to see in a player – total effort for the team cause and a desire to improve his game.
“He also relishes the contact area both in attack and defence, which is always pleasing to see.
“Now that he’s an international player he’s never looked back.
“He made a great impact in his first three outings for Scotland last year and we wish him well in the RBS 6 Nations.”