Activity in the anterior cingulate cortex (ACC) has been linked to the processes of error detection and conflict monitoring, along with the subsequent engagement of cognitive-control mechanisms. The error-related negativity (ERN) is an electrophysiological signal associated with this ACC monitoring process, occurring approximately 100 ms after an error is made. The current study examined the possibility that individual differences in ERN magnitude would predict performance outcomes related to cognitive control. Undergraduate students completed a color-naming Stroop task while their neural activity was recorded via electroencephalogram. Results indicated that a larger ERN following errors was significantly correlated with better academic performance as measured by official student transcripts. A greater ability to monitor performance and engage cognitive-control mechanisms when needed thus appears associated with improved real-world performance.