A wide range of data are obtained with self-report. Information obtained from persons using substances is generally reliable and valid, however, many studies show that some proportion of self-reports regarding substance use are inaccurate. This study examines self-reported response distortion in adolescents who received a brief intervention to reduce their smoking. Findings indicate that age and ethnicity of respondent may influence reported response distortion. Factors that appear to influence under- and over-reporting include social desirability and fear of repercussion. Response distortion does not appear to affect rated usefulness of the intervention, nor does intervention type appear to influence whether respondents thought the researcher wanted them to report less use. Results point to the need for further research regarding adolescents and response distortion.