Fear generalization is a key process in the development and maintenance of anxiety disorders. Psychobiological investigations of fear generalization have predominantly focused on defensive system activation (e.g., startle reflex), and it is unclear whether aberrant attentional processing contributes to fear generalization. The late positive potential (LPP) is an event-related potential component that indexes sustained attention and elaborative processing of motivationally salient information, and is larger in response to arousing compared to nonarousing stimuli. In the present study 48 participants completed a fear generalization paradigm using electric shocks. The LPP and retrospective risk ratings of shock likelihood were measured in response to the conditioned stimulus (CS +) and multiple generalization stimuli (GS) that varied in perceptual similarity to the CS +. In addition, intolerance of uncertainty (IU) was examined in relation to fear generalization. The LPP was enhanced for the CS + relative to the GS, but the GS did not differ from one another. Thus, overall the LPP did not reflect fear generalization. However, the LPP to the GS differed as a function of IU, such that high Prospective IU was associated with an attenuated LPP to the GS, and this was independent of trait anxiety. Risk ratings tracked fear generalization irrespective of IU. We discuss the potential influence of IU and attentional processing on fear generalization. Overall, the present study supports the LPP as a useful tool for examining individual differences in fear generalization.