Both clubs enter qualifying in the final round, having been crowned domestic champions last season, and they will kick off their crucial tie at Bern's Wankdorf Stadium.
Match preview
Having made the prestigious group stage in two of the past three seasons, Young Boys are looking to book their return to Europe's top table over the next few days; however, early-season form suggests they face a tough task to make it through the playoffs.
The reigning Swiss Super League champions are still searching for their first league win after five games, and only another famous name, Grasshopper Zurich, sit below them in the standings.
Title-winners in six of the last years, Young Boys went into the new season aiming to extend their dominance, but three straight defeats left them rock bottom, before successive 2-2 draws with FC Zurich and Yverdon Sport belatedly got some points on the board.
New boss Patrick Rahmen is therefore already under pressure to produce a quick upturn, particularly as his side have conceded no fewer than 13 goals so far.
Last season, under former coach Raphael Wicky, the Bern club finished third in a Champions League group featuring Manchester City, RB Leipzig and Red Star Belgrade, before losing in the Europa League knockout-round playoffs to Portuguese giants Sporting.
Now, they are intent on making it through to an expanded 36-team group phase, which would secure eight high-profile fixtures between September and January.
Galatasaray are also gunning for a place alongside Europe's elite, having dramatically pipped Fenerbahce to the Turkish Super Lig title in 2023-24.
It took a record tally of 102 points to see off Fener's challenge last term, and after their city rivals recently went out of Champions League qualifying in the third round, Gala are again aiming to best their bitterest foes.
Winning a third consecutive title - and the 25th in the Istanbul club's history - secured head coach Okan Buruk's place in the hotseat, but showings so far this season have been less impressive.
Following mixed results in pre-season, Gala suffered a 5-0 thrashing at the hands of Besiktas in the Turkish Super Cup, before requiring two late goals to win their opening league fixture at home to Hatayspor.
They then prevailed against Konyaspor last week, when Turkey stars Kerem Akturkoglu and Baris Alper Yilmaz were on target in a 2-1 away win.
A side that went out at the group stage of last year's Champions League - subsequently exiting in the Europa League's last 32 - now turns its attention back to the task of qualifying for UEFA's top club competition.
Young Boys form (all competitions):
W
L
L
L
D
D
Galatasaray form (all competitions):
Team News
Not only are Galatasaray set to be without Davinson Sanchez due to injury, but fellow defender Kaan Ayhan will miss the trip to Switzerland because of suspension; Derrick Kohn was sidelined by a chest infection last week and remains a doubt.
Furthermore, summer signing Gabriel Sara - who started Friday's away win against Konyaspor - has left for England, where his girlfriend will soon give birth.
Without Sanchez, Victor Nelsson could partner Abdulkerim Bardakci at the heart of a back four, while Sara's absence should see Lucas Torreira join Kerem Demirbay in central midfield.
Mauro Icardi once again leads the line, having already opened his account for the new season: the ex-Inter Milan striker registered 32 goals and 12 assists across all competitions last term, including three goals in Europe.
Meanwhile, Young Boys are unable to call upon Facinet Conte and Saidy Janko, while Switzerland international Kastriot Imeri - who spent much of last season on the treatment table - recently sustained an ankle injury that will keep him out until September.
Patrick Rahmen shuffled his pack for a resounding weekend cup win over minnows Printse-Nendaz, which saw his side rattle in 10 goals.
Cedric Itten helped himself to a hat-trick, but Silvere Ganvoula and Meschak Elia are perhaps ahead of the ex-Rangers striker in the race for selection.
Young Boys possible starting lineup:
Von Ballmoos; Blum, Camara, Husic, Hadjam; Lauper, Niasse; Elia, Ugrinic, Colley; Ganvoula
Galatasaray possible starting lineup:
Muslera; Jelert, Nelsson, Bardakci, Dubois; Torreira, Demirbay; Yilmaz, Mertens, Akturkoglu; Icardi
We say: Young Boys 1-1 Galatasaray
These clubs played out a 1-1 friendly draw in their only previous meeting, eight years ago, and that result could be replicated on Wednesday night.