<p>An external locus of control has largely been associated with worse psychological well-being. In general, patients with schizophrenia demonstrate a more external locus of control compared to non-psychiatric populations. Prior research in schizophrenia also suggests that the relationship between greater psychotic symptoms and decreased psychological well-being is stronger for individuals who endorse a more external locus of control. This relationship has not been tested in a non-clinical population. In an ethnically diverse sample of 420 participants, this study found, in line with hypotheses, that a more external locus of control was negatively associated with psychological well-being. While sub-clinical psychotic symptoms were negatively associated with psychological well-being, locus of control did not moderate the overall relationship between sub-clinical psychosis and psychological well-being as expected. Secondary analyses examined the relationships between sub-clinical psychotic symptoms, locus of control and psychological well-being by ethnicity and suggested that ethnicity moderated the relationship between an external locus of control and decreased well-being. In other words, for minorities there was a relationship between greater external locus of control and decreased well-being, but not for Whites.</p>