Background: Recent research on boredom suggests that it can emerge in situations characterized by over- and under-challenge. In learning contexts, this implies that high boredom may be experienced both by low- and high-achieving students. Aims: This research aimed to explore the existence and prevalence of boredom due to being over- and under-challenged in mathematics, for which empirical evidence is lacking. Sample: We employed a sample of 1.407 students (fifth to ninth graders) from all three secondary school tracks (lower, middle and upper) in Bavaria (Germany). Methods: Boredom was assessed via self-report and achievement via a standardized mathematics test. We used latent profile analysis to identify groups characterized by different levels of boredom and achievement, and we additionally examined gender and school track as group membership predictors. Results: Results revealed four distinct groups, of which two showed considerably high boredom. One was coupled with low achievement on the test (i.e. 'over-challenged group', 13% of the total sample), and one was coupled with high achievement (i.e. 'under-challenged group', 21%). Furthermore, we found a low boredom and high achievement (i.e. 'well-off group', 27%) and a relatively low boredom low achievement group (i.e. 'indifferent group', 39%). Girls were overrepresented in the over-challenged group, and students from the upper school track were underrepresented in the under-challenged group. Conclusion: Our research emphasizes the need to openly discuss and further investigate boredom due to being over- and under-challenged.