In 2 studies, we examined the use of validity screening items in adolescent survey data. In each study, adolescent respondents were asked whether they were telling the truth and paying attention in answering survey questions. In Study 1 (N = 7,801), the prevalence rates of student risk behaviors were significantly lower after inappropriate (invalid) responders were screened out of the sample. In addition, confirmatory and multigroup factor analyses demonstrated significant differences between the factor structures of school climate scales with valid versus invalid responders. In Study 2, student perceptions of school climate were correlated with teacher perceptions in 291 schools. A bootstrap resampling procedure compared the correlations obtained with valid versus invalid responding students in each school and found that valid responders had more positive views of school conditions and produced higher correlations with teacher perceptions. These findings support the value of validity screening items in improving the quality of adolescent survey data.