The current study examined whether punishment has direct and lasting effects on error-related brain activity, and whether this effect is larger with increasing trait anxiety. Participants were told that errors on a flanker task would be punished in some blocks but not others. Punishment was applied following 50% of errors in punished blocks during the first half of the experiment (i.e., acquisition), but never in the second half (i.e., extinction). The ERN was enhanced in the punished blocks in both experimental phases-this enhancement remained stable throughout the extinction phase. More anxious individuals were characterized by larger punishment-related modulations in the ERN. The study reveals evidence for lasting, punishment-based modulations of the ERN that increase with anxiety. These data suggest avenues for research to examine more specific learning-related mechanisms that link anxiety to overactive error monitoring.