Abstract
(1) Background: The main goals of this study were to describe the physical activity (PA) and sleep habits of 8–12-year-old children according to their gender and to evaluate the relationship between PA and sleep habits (i.e., duration and timing). (2) Methods: A total of 236 children (114 boys and 122 girls) completed the Physical Activity Questionnaire for Older Children (PAQ-C) and an ad hoc sleep habits questionnaire. (3) Results: Boys were more physically active than girls (2.62 ± 0.51 vs. 2.46 ± 0.48, p = 0.026) and enacted higher PA levels in school recess (3.82 ± 1.36 vs. 3.56 ± 1.38, p = 0.003), during the afternoon (3.37 ± 1.20 vs. 2.89 ± 1.12, p = 0.003), and during weekends (3.54 ± 1.20 vs. 3.18 ± 0.48, p = 0.009). Per sleep habits, boys had a significantly later bedtime (21:53 ± 2:08 vs. 21:34 ± 2:14, p = 0.009) and a significantly smaller total sleep duration (9.64 ± 0.86 vs. 9.89 ± 0.87 h, p = 0.023) than girls. No significant correlations between PA and sleep habits were found. (4) Conclusions: We found differences in the PA and sleep habits between school-age boys and girls. Institutions and entities should consider designing specific interventions to improve PA and sleep habits according to gender.