This study aimed to compare the effectiveness of ultrasonography and fine-needle aspiration cytology (FNAC) in distinguishing between benign and malignant thyroid nodules. To conduct this cross-sectional study, we obtained ethical approval from the institutional review board and collected data from KRL Hospital between December 1, 2021, and April 30, 2022. We included patients of either gender, aged 18 years or above, referred to the radiology department for diagnosis of benign or malignant thyroid nodules or FNAC of nodules, using non-probability consecutive sampling. After giving informed consent, all patients underwent high-resolution Gray ultrasonography performed by a consultant radiologist. The results showed that ultrasonography had a sensitivity of 90.62%, specificity of 88.37%, positive predictive value of 85.29%, negative predictive value of 92.68%, and an overall accuracy of 89.33% in detecting benign and malignant thyroid nodules, as compared to the gold standard, FNAC. Based on these findings, we conclude that ultrasonography is an excellent non-invasive diagnostic tool, with high accuracy and no invasiveness, making it the preferred method for identifying malignant thyroid nodules.