Measurement limitations have hindered research on learned helplessness (LH) and mastery orientation (MO) in the classroom. We reduced the 24-item Student Behavior Checklist to a 6-item scale and tested the abbreviated measure for evidence of reliability and validity in a sample of 5th and 6th graders (N = 299). We then replicated findings in an independent sample of middle school students (N = 116). Results demonstrated strong support for construct validity of the Student Behavior Checklist-Brief (SBC-B), including a hierarchical two-factor structure indicating the distinctness of LH and MO and an overarching construct, which we refer to as "learning approach." Results also demonstrated consistent evidence supporting criterion and convergent/discriminant validity, internal consistency reliability, and temporal stability. The SBC-B offers a psychometrically sound teacher-report measure of LH and MO.