Background: Math achievement is an important predictor of academic success. While many studies have examined math achievement in young children, studies with older children are scarce. This study focused on primary- and middle-school students, examining math achievements and cognitive control. Cognitive control was assessed referring to both domain-specific and domain-general cognitive control mechanisms and eliciting both simple and complex levels of conflict, and their association with math achievements. Methods: One-hundred-and-twenty-two participants performed two versions of a cognitive control task: a numerical Stroop task (NST; manipulating the numerical and physical size of Arabic numerals) and a perceptual Stroop task (PST; manipulating the location and direction of an arrow). For math achievements, participants performed math fluency and math curriculum tests. Results: Overall, the congruency effect was smaller in older students than in younger ones. Moreover, all participants demonstrated a similar congruency effect in the simple conflict task, whereas younger students showed a larger congruency effect in the complex conflict task. In addition, performance on the basic math fluency task was predicted by both Stroop tasks. However, performance on the comprehensive math achievement test was predicted only by the PST. Conclusions: Our results demonstrated enhanced cognitive control abilities of middle-school students and suggest that they can contribute to math achievements. We call for considering the implementation of both domain-specific and domain-general cognitive control activities as a potential approach to support math achievements.