Background The coronavirus disease 2019 (COVID-19) pandemic has negatively affected many aspects of daily life. In Saudi Arabia, many studies, using a range of assessment approaches, have examined how the pandemic has affected the mental health of both the general public and healthcare workers. However, to develop effective public-health initiatives for such crisis events, it would also be relevant to determine the pandemic’s impact on the behavioral, emotional, and social lives of Saudi children. Objective To assess, among Saudi children aged 3-15 years, the behavioral, emotional, and social changes that have occurred in their daily lives due to the COVID-19 pandemic. Materials and methods This study featured a cross-sectional design. Potential participants were approached through the most popular social media in Saudi Arabia, and the final sample size was 651 parents. As, at the time of data collection, the members of the Saudi public were requested to avoid face-to-face meetings where possible, a well-designed electronic questionnaire featuring closed-ended questions was used. Results Descriptive statistics showed that the mean age of the parents was 29±7 years (range: 20-60 years); over half (58%) were female. During the COVID-19 outbreak, one-third of children had asked to sleep in their parents’ beds. Furthermore, approximately 30% of children demonstrated increased irritability and mood swings when compared with the period before the pandemic. Concerning adaptive social behaviors, during the pandemic, 22% of children appeared calmer and 14% of children seemed more thoughtful. Our study reports more screen time, less physical activity, and reduced sleep time among children compared with the pre-pandemic period. Conclusion The COVID-19 pandemic has psychologically affected children. The present results highlight the need to reduce this psychological burden by enhancing children’s emotional resilience and involving parents in health-promotion programs aimed at mitigating the negative impacts of such public-health crises.