This work analyzed the role of interpersonal problems in interaction with ethnicity to predict psychotherapy outcome. A total of 262 individuals, who underwent psychotherapy at a counseling training facility, completed the Outcome Questionnaire-45 (OQ-45) and the reduced version of the Inventory of Interpersonal Problems (IIP-32). This study posited the following research question: Is the magnitude of the effect of ethnicity on treatment outcome conditional on certain IP dimensions (dominance or affiliation)? The purpose of this research was to determine whether or not ethnicity, represented by 3 ethnic groups (Whites, Hispanics, and Asians), was related to treatment outcome, and if this relationship was moderated by two interpersonal distress dimensions: dominance and affiliation. The results of the hierarchical regression analyses indicated that ethnicity did not predict post-treatment outcome gain, and neither affiliation nor dominance was a moderator of the relationship between outcome and ethnicity.