The 24-year-old's renewal comes as a major boost ahead of Glasgow's return to action against Edinburgh at BT Murrayfield this weekend.
The former Scotland U20 captain has made 73 appearances to date in a Glasgow jersey, his set-piece intelligence and dynamism around the park making him a key asset in the Warriors setup.
Cummings was a key member of the Warriors squad that reached Heineken Champions Cup quarter-finals in 2017 and 2019, whilst the second-rower was integral to Glasgow's run to the 2019 Guinness PRO14 Final at Celtic Park.
His form in that run saw him earn a first senior Scotland cap against France in the summer of 2019, before being selected for the 2019 Rugby World Cup in Japan.
Since making his Scotland debut, he has been an ever-present in international matchday squads; the second-rower has been involved in 17 consecutive Test matches across the Rugby World Cup, 2020 Guinness Six Nations and the 2020 Autumn Nations Cup.
Speaking following the announcement, Cummings told glasgowwarriors.org: "Staying at Glasgow was quite an easy decision for me.
"Getting to play for the club that I grew up supporting is an amazing feeling. We've got a great, hard-working group of guys that want to push on.
"I've really enjoyed the past six years at the club. There's nothing better than running out at Scotstoun when the stadium is packed, and I can't wait until it's safe to welcome fans back to match nights at Scotstoun.
"I still feel like this team has the ability to push on and compete with the best teams in Europe. I just want to continue enjoying my rugby with Glasgow and represent this club and this city as best I can."
Glasgow Warriors Head Coach Danny Wilson was delighted to have secured the signature of Cummings, a man identified by many as a potential contender for the 2021 British and Irish Lions tour of South Africa.
"Scott is an good athlete and someone with a fantastic rugby brain" Wilson told glasgowwarriors.org.
"Having worked with him when I was with Scotland, I knew how talented an individual he is. From my experience at Scotland and Glasgow I've been ever more impressed with absolute hunger and desire Scott has to push himself to be the best rugby player he can be.
"I'm excited about the potential that Scott has and we're delighted that he’s chosen to extend his contract with us. He's a proud Glaswegian, and he's someone that will do whatever it takes to help this club succeed."