Boys - Ending Explained

The Turning Point: Sieger initially rejects Marc to maintain his social standing and date Jessica. However, during the championship relay, the team wins gold. At the victory dinner, Sieger looks around and realizes the applause feels empty without Marc (who has been distanced).
The Ending: In a decisive moment, Sieger leaves the celebration. He takes his brother's motorbike (defying his father's earlier ban) and drives to Marc. The final shot is Sieger driving the bike with Marc on the back, embracing him. It is a clear visual statement that Sieger has chosen love over fear and is now steering his own life.

The 'Dream' Ending: While most view the ending—Sieger riding the motorbike with Marc on the back—as literal, some critics have suggested it has a dreamlike quality. The motorbike was previously forbidden and associated with death; Sieger riding it could symbolize a metaphorical departure from his father's rules rather than a literal road trip. However, the general consensus is that it represents a literal and triumphant choice.

The Race as Life: The relay race can be read as a metaphor for the 'script' of heteronormative life (pass the baton, finish the race, get the girl). Sieger winning the race but feeling empty is the film's rejection of this script.