ABSTRACT Self-concept clarity (SCC) refers to the extent to which self-beliefs are clearly and confidently defined, internally consistent, and stable. While there is an abundance of research showing an association between SCC, well-being, and effective self-regulation, there is little knowledge about how SCC relates to basic cognitive processes such as attention and memory. Drawing on the attentional function theory of cognitive control, we hypothesized that low SCC is associated with greater attentional control during a trait assessment task. We also expected that low SCC individuals retrieve self-related information from semantic memory less efficiently compared to high SCC individuals. Fifty participants took part in the ERP study. The P300 and N400 components were measured as electrophysiological indices of attentional and semantic processing. The results showed that individuals with low SCC had larger P300 amplitude in response to positive versus negative words, and marginally larger P300 amplitude in response to positive words compared to high SCC individuals. These results suggest greater attentional involvement in the processing of positive self-related information in people with low SCC. There were no significant differences between groups in N400 amplitude. The results are discussed in the context of the relationship of SCC to self-esteem and self-motive theory.