Objectives: An early and precise diagnosis is important to confirm acute appendicitis (AA) in children. Ultrasound imaging techniques have demonstrated higher value in the diagnosis of AA. This study was conducted to ascertain the nondiagnostic and diagnostic rates of U/S examinations for appendicitis in children and possibly examine the causes of these high failure rates. Material and Methods: All abdominal and appendiceal U/S examinations for patients ?16 years old that were performed at King Saud University Medical City (KSUMC), Riyadh, Saudi Arabia, between April 2019 and December 2021 (approximately 32 months) were retrospectively examined and evaluated after the local ethics committee gave its approval for the study. Final ultrasound reports were categorized as “positive,” “negative,” “borderline,” or “not visualized.” Results: During the 32 months, 112 results of patients (62, 55.4% males and 50, 44.6% females), who underwent ultrasound (U/S) of the appendix were performed, reviewed, and analyzed (mean age, 10.59 ± 2.9 years). The rate of U/S non-diagnostic results was recorded in 77 (68.8%) cases, whereas 35 studies (31.2%) were classified as diagnostic. Of all the 35 diagnostic U/S studies, seven had follow-up CT scans, which showed five (35.7%) positive and two (14.3%) negative results. On the other hand, of the 77 non-diagnostic ultrasound (U/S) scans, seven had follow-up CT scans, which showed 3 (21.4%) borderline and 4 (28.6%) non-visualized appendices. There was no significant difference in the rate of US non-diagnostic results according to gender or the procedure performed. U/S sensitivity was 47.1%, specificity was 87.5%, positive predictive value was 87.5%, and negative predictive value was 47.5%. Conclusion: We found a high rate of nondiagnostic tests for appendicitis. A comprehensive reassessment of the patient is required, and a second US may be necessary to confirm the diagnosis. It is recommended that implementing a standard US report template based on validated secondary appendicitis signs, assessment of appendiceal size, and improved techniques from a graded compression US to CT or MRI would improve diagnostic accuracy.