The Parkhead side use Thistle's Glasgow home for Clydesdale Bank Under 20 Premier League fixtures and now have signed a deal that will have them take to the field in European competition this season.
The first Firhill fixture will be a clash against Aston Villa on October 24, with Thistle set to benefit from added income by hosting the Euro glamour ties.
Jags General Manager Ian Maxwell said: "With the Glasgow Warriors leaving at the end of last season, it was important we tried to replace the revenue we'd lost.
"A ground-share agreement was an option, but we had to make sure it worked for us.
"The stadium is our biggest asset and it makes sense to maximise any income from it.
"So when Celtic expressed an interest in holding games here, it made sense to look at it.
"The deal we have agreed will have Celtic play a mixture of SPL U-20 League and NextGen Series games here at Firhill.
"It is structured in such a way that a split of the receipts from games at Firhill will stay with PTFC.
"With Celtic up against the likes of Sporting Lisbon, Aston Villa and PSV Eindhoven in the NextGen competition it means Jags fans can not only get to see some European stars of the future they will also be helping the club."