Sleep apnea (SA) is a disease widely known for affecting adults. However, SA in children is increasing and gaining awareness. Overnight in-laboratory polysomnography (LPSG) is considered the gold standard in the diagnosis of SA. Nevertheless, LPSG is expensive, time consuming, technically complex, and requires the patient be at the laboratory. This has made finding alternative diagnostic and screening methods urgently needed. Timely diagnosis and management of pediatric SA is critical to prevent progressive associated comorbidities. Several studies have attempted to investigte alternative SA diagnostic methods in adults. However, such studies in pediatric patients are scarce. The pathophysiology and management of SA is different between adults and children which does not allow adult-specific data to be extrapolated to children. In the present study, we compared LPSG to several other diagnostic methods in children. The apnea-hypopnea index (AHI) generated by the LPSG was used as a means for comparison. In terms of questionnaires, we chose the most commonly used pediatric sleep questionnaire, the PSQ, and a recently proposed shorter questionnaire, the Gozal questionnaire (6Q). We also compared two-dimensional (2D) and three-dimensional (3D) radiographic analyses to LPSG. Finally, we compared a portable monitor, the MediByte, simultaneously with the LPSG. The 6Q performed better than the more commonly used PSQ, both in terms of correlating with AHI and predicting severe SA. Both 2D and 3D radiographic airway analyses had variables that significantly correlated with AHI, especially with regards to adenoid measurements. Contrary to finding in adults, the adenoid and nasopharyngeal measurements might be of great importance when screening for pediatric SA. Additionally, we proposed questionnaire and radiographic cut-off values that can assist clinicians in the screening process of SA in children. The AHI generated by the portable monitor strongly correlated with the AHI from the LPSG. Moreover, the sensitivity and specificity for severe SA was very high. Although LPSG is still recommended for the diagnosis of SA, portable monitors can play a great role in diagnosing moderate and severe SA especially in older pediatric patients. Furthermore, the Gozal sleep questionnaire and radiographic airway analyses can greatly help in the screening for pediatric SA.