The ability to make rapid and precise decisions regarding the presence or absence of threats in our environment is critical for our survival. While threatening stimuli may be detected more accurately and faster due to the "bottom-up" salience of their features, in the real-world, these stimuli are often encountered in familiar environments in which "top-down" cues signal their arrival. There has been significant progress in our understanding of the mechanisms by which we make perceptual decisions regarding relatively routine stimuli; however, the mechanisms of threat-related perceptual decision-making remain unclear. In this paper, we discuss the psychological, computational, and neural mechanisms by which information from threatening stimuli is integrated with our prior knowledge from cues and surrounding contexts to guide perceptual decision-making.