Background: Errors can provide informative feedback and exhibit a high potential for learning gains. Affective-motivational and action-related reactions to errors are two forms of error adaptivity that have been shown to enhance learning outcomes from errors. However, little is known regarding the development and contextual conditions of students' error reactions. A theoretically plausible facilitator to this end is the perceived error climate in the classroom. Aim: We investigated how students' dealing with errors develops over time and which role the classroom context in general, and the perceived error climate in particular, has for this development. Sample: A total of 1641 students participated in 69 mathematics classrooms in academic secondary schools. Methods: Perceived error climate alongside students' self-reported individual reactions to errors were assessed in a 2-year longitudinal study with five measurement points over the fifth and sixth grade. Results: Growth-curve modelling indicated an, on average, negative development of students' individual reactions to errors. This development varied substantially between classrooms and systematically depended on perceived error climate. A more positive error climate was associated with a less negative development of error adaptivity. Conclusion: Taken together, our findings imply a strong need and considerable room for the teachers' support in developing and maintaining adaptive reactions to errors. They also allow for the conclusion that teachers can succeed here by means of realizing a positive error climate in class.