<p> Evidence suggests a relationship between literacy and numeracy skills and cognitive abilities, which could be improved by augmented reality (AR) games. This study aimed to investigate to what degree the performance in a literacy and numeracy skills AR game explains associations between total reaction time (TRT) and educational achievement measures. Eighty-three participants with intellectual disabilities, aged 6 to 17 (with and without Down syndrome), and 37 participants from public schools with typical development participated in a cross-sectional study. TRT was measured using the TRT_S₂₀₁₂ software, and performance on AR tasks was assessed with the <i>MoviLetrando</i> game. The analysis of variance revealed that the improvement in TRT overall performance on the second attempt (M = 1.70) compared to the first (M = 1.85) was not significant, with F(1,99.00) = 0.76, <i>p</i> =.39, ŋ²=0.01. Post hoc comparisons indicated that the group with typical development performed significantly faster in overall scores on the TRT scale when compared to the groups with Down syndrome and intellectual disabilities (<i>p</i> &lt;.001). These two groups reported similar performances (M = 2.65ms; M = 1.87ms, respectively) in the TRT task after performing the AR game, but both showed lower performance compared to the typical development group (M = 0.59ms), the main effect for group was F(2,99) = 14.04, <i>p</i> &lt;.01, ŋ²=0.22. Educational achievement measures were strongly correlated with TRT and each <i>MoviLetrando</i> subscale. The group with Down syndrome was able to achieve the average time in the most complex task. The performance of participants with intellectual disabilities was delayed compared to their peers with typical development. Educational achievement measures and TRT explain the associations between these performances.</p>