Due to their connections with positive educational outcomes, the maintenance of good health and scholastic well-being are highly relevant topics. However, to date, no studies have investigated developmental changes in scholastic well-being in the light of achievement emotions and instructional quality--although these predictors offer good approaches for intervention. A sample of N = 667 (age: M = 10.16; SD = 0.46; 81.7% female) students was questioned three times over one year, from the beginning of their fifth grade into sixth grade, using reliable questionnaires. The results of multilevel linear growth curve modelling calculations show that a decrease in scholastic well-being during the fifth grade was induced by changes in the predictors (achievement emotions and instructional quality). Since the highest effects are evident regarding achievement emotions, support programs should focus on facilitating these aspects in secondary school children.