<p>This study evaluated the effects of the purposes of the homework given by teachers (preparatory homework, reinforcement homework, and extension homework) on the learning levels of the students. In this study, technical/scientific/collaborative design, one of the action research types, was used. The research was conducted with three teachers teaching 4th-grade primary school, including the researcher. The research was conducted on a total of 86 fourth-grade students studying in three different classes. This study was carried out in the “Lighting and Sound Technologies” unit in the 4th grade primary school Science course curriculum, and the time allocated to this unit is 21 (twenty-one) lesson hours. The action plan was designed to be used for different homework purposes (reinforcement, preparatory, extension), and different homework assignments were developed to be used in the plan. Multiple choice and tests prepared according to SOLO taxonomy were used as data collection tools. In the analysis of the data obtained, it was concluded that all of the different homework purposes contributed to learning, but extension homework was more effective than other homework purposes. After extension assignments, preparatory assignments are the other assignment purpose that increases student success. Additionally, it was concluded that homework increased student success in three different classes and that the purpose of homework that increased success the most was extension homework.</p>