Methods for measuring homework performance have been limited primarily to parent reports of homework deficits. The Homework Performance Questionnaire (HPQ) was developed to assess the homework functioning of students in Grades 1 to 8 from the perspective of both teachers and parents. The purpose of this study was to examine the factorial validity of teacher and parent versions of this scale, and to evaluate gender and grade-level differences in factor scores. The HPQ was administered in 4 states from varying regions of the United States. The validation sample consisted of students (n = 511) for whom both parent and teacher ratings were obtained (52% female, mean of 9.5 years of age, 79% non-Hispanic, and 78% White). The cross-validation sample included 1,450 parent ratings and 166 teacher ratings with similar demographic characteristics. The results of confirmatory factor analyses demonstrated that the best-fitting model for teachers was a bifactor solution including a general factor and 2 orthogonal factors, referring to student self-regulation and competence. The best-fitting model for parents was also a bifactor solution, including a general factor and 3 orthogonal factors, referring to student self-regulation, student competence, and teacher support of homework. Gender differences were identified for the general and self-regulation factors of both versions. Overall, the findings provide strong support for the HPQ as a multi-informant, multidimensional measure of homework performance that has utility for the assessment of elementary and middle school students.