This study examined the influence of social identity and the intimacy of relationships on uncertainty reduction processes in interethnic relationships. Data from two samples (Hispanics in the Midwest and Caucasians in the Southwest) were used to test hypotheses derived from social identity theory (e.g., Tajfel & Turner, 1979) and theories of relationship development (e.g., Altman & Taylor, 1973). Results for both samples revealed that social identity has a significant positive effect on uncertainty reduction processes. This effect, however, was moderated by prototypicality; that is, it occurred in relationships where the partner was viewed as “typical,” but not in relationships where the partner was viewed as “atypical.” When controlling for the partner's ethnicity in the Caucasian analysis, social identity had a significant effect on communication with black partners, but not with Mexican-American partners. This finding was explained by status characteristic theory (e.g., Berger & Zelditch, 1985). The intimacy of interethnic relationship also accounted for a significant portion of the variance. The effect for intimacy was manifested in relationships where the partner was viewed as typical, as well as when the partner was viewed as atypical. The results are consistent with social identity theory and recent work linking it with uncertainty reduction theory, as well as with theories of relationship development.