Sleep-disordered breathing is associated with impaired attention and neurocognitive deficits. We assessed the association of snoring and intermittent hypoxia with poor academic performance in third grade school children (1,144 children). Snoring frequency and intermittent hypoxia were investigated using parental questionnaire and nocturnal home pulse oximetry. Intermittent hypoxia was specified as desaturation events of 90% or less pulse oximeter saturation. Poor academic performance was defined as grade 4-6 on a six-point scale (i.e., approximately the lowest quintile grades) in mathematics, science, reading, spelling, and/or handwriting in the most recent school report. Snoring "always" was significantly associated with poor academic performance in mathematics (odds ratio; 95% confidence interval: 3.6; 1.3-10.1), science (4.3; 1.3-14.6), and spelling (3.5; 1.2-10.3). Snoring "frequently" was also significantly associated with poor academic performance in mathematics (2.4; 1.3-4.7) and spelling (2.0; 1.04-3.8). A significant relationship between snoring and poor academic performance was also found in children without intermittent hypoxia, whereas intermittent hypoxia did not show an independent association with poor academic performance. Thus, habitual snoring (i.e., snoring frequently or always) was associated with poor academic performance in these primary school children.