Limited research exists regarding the role of teachers in screening for Autism Spectrum Disorders (ASD). The current study examined the use of the Social Communication Questionnaire (SCQ) and Social Responsiveness Scale (SRS) as completed by parents and teachers about school-age children from the Simons Simplex Collection. Using the recommended cutoff scores in the manuals and extant literature, the teacher-completed SCQ and SRS yielded lower sensitivity and specificity values than would be desirable; however, lowering the cutoff scores on both instruments improved sensitivity and specificity to more adequate levels for screening purposes. Using the adjusted cutoff scores, the SRS teacher form appears to be a slightly better screener than the SCQ. Implications and limitations are discussed, as well as areas for future research.