The superior colliculus (SC) is a major recipient of visual input in the mouse and controls innate approach and avoidance behaviours. Neurons in the superficial SC (sSC), which receives direct input from the retina, do not only process visual stimuli, but are also modulated by the animal’s running speed and pupil-linked arousal, similar to modulations observed in the primary visual cortex. While these observations were made during passive viewing of visual stimuli, a major purpose of vision is to guide behaviour. We therefore asked whether, in the context of a behavioural task, visual activity in the sSC is modulated by states or variables other than pupil-linked arousal. We trained mice to perform a visual detection task, where they needed to detect a stimulus of varying contrast in the left or right visual field and then interactively move the stimulus towards the centre of the visual field. If no stimulus was presented, the mice had to refrain from moving the stimulus. After correct choices, the mice received water reward; after incorrect choices, auditory white noise was played instead. We expressed GCaMP6f in sSC neurons and used two-photon imaging to record neural activity in trained mice performing the task. Simultaneously, we monitored the mouse’s pupil size. Similar to previous studies, we found that pupil-linked arousal modulated the visual responses of sSC neurons. Additionally and independently of this modulation, previous reward strongly increased the subsequent visual responses, while negative feedback was followed by weaker visual responses. This modulation by previous feedback could not be explained by licking. Our findings show that visual responses of sSC neurons are strongly influenced by two independent state variables: pupil-linked arousal and previous reward. Future studies may reveal how these non-visual modulations help downstream processes in guiding behaviour.