Ethical guidelines require school psychologists to ensure that their assessment practices are nondiscriminatory, but typical discussions on this topic neglect the possible discriminatory effects of cultural stereotypes on assessment results. Recent research on "stereotype threat" shows that students' knowledge of stereotype-based negative expectations about their test performance can depress their actual test performance. This paper discusses the range of conditions that promote stereotype threat and identifies important moderators and mediators of the phenomenon. Several practical suggestions are offered for school psychologists to consider when interviewing students, interpreting assessment results, and developing programs to increase schoolwide achievement.