Background: Gallbladder function plays a crucial role in the management and outcomes of patients with common bile duct (CBD) stones. Common bile duct stones are a significant cause of morbidity, often resulting in complications like cholangitis, pancreatitis, and biliary colic. While endoscopic and surgical interventions have advanced, predicting the occurrence of complications remains challenging. The gallbladder plays a pivotal role in bile storage and secretion, and its dysfunction may exacerbate biliary pathology. However, its predictive value for subsequent biliary complications remains unclear. This study aims to assess the relationship between gallbladder function and the incidence of biliary complications in CBD stone patients. Methods: We conducted a retrospective analysis of 80 patients diagnosed with CBD stones. Gallbladder function was evaluated using preoperative imaging and laboratory tests, and patients were followed up for biliary complications over a 12- month period. Gallbladder function was evaluated using hepatobiliary scintigraphy (HIDA scan) to assess the ejection fraction (EF). An EF below 35% was considered indicative of gallbladder dysfunction. Other imaging modalities, such as ultrasound and magnetic resonance cholangiopancreatography (MRCP), were used to confirm the diagnosis of CBD stones. Results: The study included 80 patients with a mean age of 60 ± 8.2 years. Of the cohort, 55% were male, and 45% were female. The majority of patients presented with symptoms of biliary colic (68%), followed by jaundice (45%), and fever (25%). The notable proportion of patients (40%) had impaired gallbladder function (EF < 35%), indicating that gallbladder dysfunction is common in this patient population. The even distribution across higher EF ranges (35–70%) reflects a broad spectrum of gallbladder performance among patients without severe dysfunction. Patients with EF < 35% had a significantly higher incidence of biliary complications (40.6%) compared to those with EF ≥ 35% (10.4%). Cholangitis was the most common complication, occurring in 31.3% of patients with EF < 35%, compared to only 6.3% in patients with normal EF. Similarly, pancreatitis was more prevalent in the impaired EF group (15.6% vs. 4.2%), further emphasizing the role of gallbladder dysfunction in increasing complication risks. Conclusion: Impaired gallbladder function can predict biliary complications in patients with CBD stones. Preoperative assessment of gallbladder function may help guide treatment decisions and improve patient outcomes