Sleep has become less important in western society during modern times, where many have the habit of prioritizing productive activities instead of sufficient sleep. However, recent studies have indicated the importance of sleep for emotional processing. A crucial finding in literature regarding sleep and emotions has been the enhancement of negative emotions after sleep deprivation. The aim of this systematic literature review was to investigate the neural basis of the effects of sleep deprivation on emotional reactivity. In order to conduct this review, three databases were used to obtain relevant articles. Out of the total 1041 articles, 11 fulfilled the inclusion criteria and were included in the review. The selected articles exclusively contained results regarding reactivity to visual emotional stimuli. Results showed that total and partial sleep deprivation result in enhanced amygdala activity in response to negative stimuli. Enhanced amygdala activity was also found in response to positive and neutral stimuli after sleep deprivation. The insula was another brain region that displayed enhanced activity toward all types of valenced stimuli after sleep deprivation. Moreover, weaker connectivity between the amygdala and prefrontal areas (specifically the medial prefrontal cortex) was found after total and partial sleep loss. Together, these results suggest that sleep deprivation induces hyperreactivity toward emotional stimuli and disrupts top-down regulation of emotional reactivity.