Self-construals have been advanced as individual level cultural dimensions, and are thought to explain and mediate the effects of culture on a variety of outcome measures. This study (total N = 439) investigated the effects of self-construals on the attitudinal and normative components of the Theory of Reasoned Action (TRA) in Korea, Hawaii, and the mainland United States. Self-construals were investigated as both mediators and moderators of cultural effects. Across cultures, the data were consistent with the TRA, scores on independent self-construal were positively related to personal attitudes toward behavior, and scores on interdependent self-construal were positively related to normative beliefs and social attitudes toward behavior. Specific effects, however, varied from location to location suggesting a moderating role for self-construals. Mixed results were obtained for the link between culture and self-construals, and for the mediation model. Individuals in all three locations scored higher on independence than interdependence, and culture appeared to affect the extent to which individuals distinguished between types of self-construal. Taken together with previous findings, these findings suggest that it may be necessary to rethink the role of self-construals in intercultural research.