Commonly used literacy motivation assessments do not specifically explore literacy motivation in school. These context-general assessments may be problematic for struggling adolescent readers, as qualitative research documents that these adolescents exhibit different levels of cross-context motivation. The present study explores whether an in-school measure predicts additional variance in reading performance beyond a non-context-specific measure. One hundred and fifteen fifth graders were administered the Motivation for Reading Questionnaire, an in-school reading motivation daily log, a demographic survey, and standardized reading assessments. Findings indicate that the in-school reading motivation measure predicted performance for struggling readers and the non-context-specific measure did not.