According to interdependence theory, interpersonal situations that vary in their surface characteristics can be united by similarities in their underlying structure. Likewise, factor analytic approaches to personality combine many traits into a small number of factors. In the current research, we use interdependence theory and existing factor analyses of personality traits to measure people's lay theories about the ways traits and situations interact. We predict that traits representative of honesty–humility/virtue will be rated as more relevant to situations with non-correspondent outcomes (a gain in one person's outcomes is associated with a loss in the other person's outcomes) than to situations with correspondent outcomes (a gain in one person's outcomes is associated with a gain in the other person's outcomes). Conversely, we predict that traits representative of agreeableness will be rated as more relevant to situations with correspondent outcomes than to situations with non-correspondent outcomes. An experiment found the expected trait X situation interaction revealing that subjects expect certain types of traits to be most relevant to specific types of situations. Copyright © 2013 John Wiley & Sons, Ltd.