The aim of this study was to develop and validate Science Homework Scale (SHS) which assesses middle-school (grades 6-8) students' perceptions of teachers' homework practices and homework self-regulation in science. Students' perceptions of teachers' homework practices included homework quality and feedback on homework while students' homework self-regulation consisted of homework goal orientations (i.e. mastery, performance, and work-avoidance), homework strategy use (i.e. deep learning and management), and homework procrastination; 3 studies were conducted with 7th-grade Turkish students. In study 1 (n = 618), the data were analyzed through exploratory factor analyses. In study 2 (n = 758), in order to test the hypothesized factor structure, the data were subjected to confirmatory factor analyses (CFAs). Goodness-of-fit indices indicated good model fit and Cronbach alpha reliabilities of subscales ranged from 0.77 to 0.96. Additionally, multi-group CFAs supported factorial invariance of SHS across boys and girls. In the 3rd study (n = 8318), CFA results supported 8-factor structure. Next, a homework model which suggested relationships among students' perceptions of teachers' homework practices, homework self-regulation, and achievement was proposed. Hierarchical linear modeling (HLM) analyses results revealed that students' perceptions of homework quality and feedback on homework were associated with homework self-regulation components which in turn related to science achievement.