Although the elder of the two brothers, Max, had already signed an extension to his current contract, this latest development will see both siblings stay together in Scotland until after the next Rugby World Cup.
Head coach, Sean Lineen said: "We're obviously delighted that both Thom and Max have committed to Glasgow Warriors and Scottish Rugby for the next two years.
"They are both exciting talents and that's abundantly clear when they have the ball in hand. The crowd just go ballistic when they are in action at either Murrayfield or Firhill. They're two very refreshing talents to have around the Scottish game.
"It's a good move at this stage in their development as they are still learning. It's good to see that their decision is not all about money, but the opportunity to grow with a club that will look after them at this stage in their careers."
Max, who scored Scotland's only try in his Murrayfield debut during the opening game of the RBS 6 Nations championship against Wales, said: "I've always been very happy in Glasgow and now that's even more-so given that Thom and I will be together until 2011.
"We just want to dedicate ourselves to Glasgow Warriors and Scottish Rugby as the next World Cup fast approaches."
Thom, who also found the whitewash for the national team, this time a week later in the Stade de France, added: "I'm really excited with the way Scottish Rugby is going at the moment and obviously, since I've been at Glasgow, I feel that each season we've got better as a team.
"Our performances are improving and with Chris Cusiter on board for next season it's a big statement of how ambitious we are at Glasgow.
"There is more competition in the Scotland squad than ever before, so it's important that I stay in Scotland to increase my chances of playing for my country. I'm delighted to be staying at Glasgow and it's important to me that Max is alongside me too. I feel it is very much the right decision for me to commit to Glasgow until 2011."
Glasgow Warriors chief executive, Ian Riddoch, is also delighted with the news: "Max and Thom have started to fulfil their potential since joining the Warriors and have both grown into exciting international rugby players.
"We have seen an increase in attendances since moving to Firhill at the beginning of last season and we are retaining our best players and recruiting outstanding Scottish talent such as Chris Cusiter. Glasgow's stock is rising and I'm sure every Warriors fan will join me in anticipating a bright future for the Warriors."
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