Whites’ nonprejudiced behavior toward racial/ethnic minorities can be attributionally ambiguous for perceivers, who may wonder whether the behavior was motivated by a genuine internal commitment to egalitarianism or was externally motivated by desires to avoid appearing prejudiced to others. This article reports the development of a scale that measures perceptions of Whites’ internal and external motives for avoiding prejudice (Perceived Internal Motivation Scale/Perceived External Motivation Scale [PIMS/PEMS]) and tests of its internal, test–retest, discriminant, convergent, and predictive validity among ethnic minority perceivers. Minorities perceived Whites as having internal and external motives for nonprejudiced behavior that were theoretically consistent with but distinct from established measures of minority-group members’ concerns in interracial interactions. Tests of the predictive validity of PIMS/PEMS showed that when a White evaluator praised the mediocre essay of a minority target, minorities who were high PEMS and low PIMS were most likely to regard the feedback as inauthentic and derogate the quality of the essay.