This study examines the relationship between aspects of homework quality (embedding homework in the teaching-learning process and differentiation), students' anger experienced while completing German homework (language of instruction), and orthography performance. In total, 410 students from 23 eighth-grade classes in the Swiss canton of Bern have been surveyed. To date, no studies have investigated the relationship between either of the two qualitative aspects and anger as a specific emotion. Multilevel mediation models showed that at the student level, students' anger about homework contributed to a significant indirect effect of perceived embedding of homework in the teaching-learning process on students' orthography performance. However, no significant indirect effect of perceived differentiation in homework on performance was found. The results can guide the adaptation of the training and further education of teachers to enable them to give high-quality homework that does not trigger anger in students and, conversely, can positively impact their performance.