It's Glasgow's only home friendly ahead of the new season with kick-off scheduled for 7.30pm.
Speaking following the announcement, Head Coach Franco Smith told glasgowwarriors.org: "We look forward to welcoming Northampton to Scotstoun this September, in what will be a key milestone in our pre-season preparations.
"Their performances both in the Premiership and Investec Champions Cup last season showed the strength in depth that their squad possesses, with their brand of rugby set to provide us with a valuable test in both attack and defence ahead of the new season.
"The match will also be an important opportunity for our academy and young players to put their hands up for selection; we saw the impact that players such as Jare Oguntibeju and Macenzzie Duncan made last season following their game time in pre-season, as we look to continue the development of young, Scottish talents within our playing group."
The match is included in a 2025/26 Season Ticket, with the East and West Stands scheduled to be in place ahead of the fixture. The match will not be broadcast.
Tickets will go on general sale in the coming weeks.