This paper presents a conceptual model for guiding research on homework. Based on elements derived from a review of 26 recent U.S. and international empirical studies of homework, the model emphasizes the need to consider many variables in order to reach an understanding of the design and conduct of homework assignments, homework completion, and the effects of the two activities on student learning and development. Specific independent variables included in the model concern student and family background, teacher background, school organization and policy, classroom organization and classwork, and core independent variables of homework assignments by teacher, homework completion by students, and homework return and follow-up. Dependent variables concern effects on student learning and development, and effects on teaching practice. Each variable is particularized in detail. The model is offered as a complete, realistic theoretical model that can be tested as a measurement model in new research. Variables, or subsets of variables, can be tested with cross-sectional or longitudinal data, in recursive or nonrecursive designs and analyses, and using qualitative or quantitative data to address new and needed questions about homework assignments, completion, and impact. Approximately 50 references are listed. (RH)