ObjectivesThis study examined several underlying mechanisms hypothesized by the Environmental Stress Hypothesis (ESH) to explain the association between probable Developmental Coordination Disorder (pDCD) and internalizing problems. Design/MethodA cross-sectional analysis involving 1206 children aged 12–14 years (79 pDCD, 6.6% of the sample) was conducted. Children received assessments of motor coordination, physical activity, BMI, global self-worth, and internalizing problems. Path analysis was conducted to examine overall model fit and sex differences. ResultsThe results showed significant sex differences in the underlying pathways connecting pDCD to internalizing problems, indicating more mediating pathways through physical activity, BMI and global self-worth in girls, compared to boys. ConclusionsOverall, we were able to find support for some of the pathways identified in the ESH in school-aged children. Results also suggest that the development of interventions may need to be sex specific.