Objective: The main goal of the current study is to investigate whether intrinsic motivation and behavioral engagement mediate the association between inattention symptoms and academic achievement (reading, writing, and mathematics), as well as to document the extent to which inattention symptoms contribute to academic achievement due to variance overlapping with intrinsic motivation and behavioral engagement. Method: Participants were 92 children (Grades 1-4). Data were gathered using a combination of parent and teacher reports as well as objective assessments. Results: Results did not support the mediating role of intrinsic motivation and behavioral engagement. A commonality analysis showed that 77.44% to 82.10% of the variance explained in each academic achievement domains was due to variance shared by inattention symptoms, intrinsic motivation, and behavioral engagement. Conclusion: These results suggest more commonality than differences between inattention symptoms, intrinsic motivation, and behavioral engagement with regard to their association with academic achievement. The implications of these findings are discussed.