Research on “stereotype threat” (Aronson, Quinn, & Spencer, 1998; Steele, 1997; Steele & Aronson, 1995) suggests that the social stigma of intellectual inferiority borne by certain cultural minorities can undermine the standardized test performance and school outcomes of members of these groups. This research tested two assumptions about the necessary conditions for stereotype threat to impair intellectual test performance. First, we tested the hypothesis that to interfere with performance, stereotype threat requires neither a history of stigmatization nor internalized feelings of intellectual inferiority, but can arise and become disruptive as a result of situational pressures alone. Two experiments tested this notion with participants for whom no stereotype of low ability exists in the domain we tested and who, in fact, were selected for high ability in that domain (math-proficient white males). In Study 1 we induced stereotype threat by invoking a comparison with a minority group stereotyped to excel at math (Asians). As predicted, these stereotype-threatened white males performed worse on a difficult math test than a nonstereotype-threatened control group. Study 2 replicated this effect and further tested the assumption that stereotype threat is in part mediated by domain identification and, therefore, most likely to undermine the performances of individuals who are highly identified with the domain being tested. The results are discussed in terms of their implications for the development of stereotype threat theory as well as for standardized testing.