Stress is considered to be a key factor in the development and maintenance of dysfunctional reward processing, such as in clinical disorders like addiction. In fact, stress induces physiological modulations that interact with reward circuits in the brain, thereby enhancing stimulus-driven control and suppressing goal-directed control over reward-seeking behaviours. The present work thus aimed at testing this neuromodulation hypothesis at the behavioural level. Accordingly, twenty male participants performed a Pavlovian-instrumental conflict task, which was designed to parse stimulus-driven and goal-directed processes, with a stress manipulation while measuring their anticipatory visual behaviour toward rewards by means of an eye tracker. Computational modelling analyses revealed that stress specifically affects stimulus-driven and goal-directed processes integration rather than how these systems learn. This suggests that stress exposure can bias behavioural control independently from learning, which would be a plausible explanation for the resistance of reward processing disorders to interventions on the long term.