Introduction: Acute appendicitis is one of the most common causes of acute abdominal pain requiring surgical intervention. Accurate and timely diagnosis is crucial to minimize complications such as perforation and peritonitis. Ultrasound has emerged as a valuable, non-invasive imaging modality in diagnosing acute appendicitis, particularly in scenarios where clinical diagnosis is challenging. This study aims to evaluate the diagnostic accuracy of ultrasound in detecting acute appendicitis in a sample size of 90 patients presenting with suspected appendicitis at a tertiary care hospital. Materials and Methods: This prospective observational study was conducted at a tertiary care teaching hospital over six months. A total of 90 patients presenting with acute abdominal pain and clinical suspicion of appendicitis were included in the study. Patients of all genders aged 10 years and above. Clinical suspicion of acute appendicitis based on symptoms (right lower quadrant pain, fever, nausea, etc.) and physical examination (e.g., McBurney’s point tenderness) were included. The sonographic diagnosis was categorized as positive, negative, or equivocal for appendicitis. All patients subsequently underwent surgical evaluation, and appendectomy specimens were subjected to histopathological examination, which served as the gold standard for diagnosis. Results: An enlarged appendix (>6 mm) was the most frequent finding (64.4%), followed by non- compressibility (58.9%). Periappendiceal fat stranding and free fluid were less common but still significant markers of inflammation. Sensitivity (84.6%): Ultrasound correctly identified 84.6% of patients with acute appendicitis, indicating its ability to detect true positive cases effectively. Specificity (78.3%): Ultrasound correctly ruled out acute appendicitis in 78.3% of patients without the condition, though some false positives were noted. PPV (91.3%): High predictive value of a positive ultrasound suggests reliable confirmation of appendicitis when ultrasound findings are positive. NPV (66.7%): The lower negative predictive value emphasizes the risk of missed diagnoses in cases of negative ultrasound, particularly in atypical presentations. Conclusion: Ultrasound is an effective first-line imaging modality in diagnosing acute appendicitis, offering high sensitivity and specificity. Its non-invasive nature and lack of radiation make it particularly suitable for vulnerable populations such as children and pregnant women. While limitations exist, the integration of ultrasound with clinical and laboratory findings can significantly improve diagnostic efficiency, reducing negative appendectomy rates and associated complications.