Thyroglossal duct cysts (TGDCs) are the most common congenital neck masses, frequently diagnosed in both pediatric and adult populations. Accurate preoperative diagnosis and imaging are essential for effective management. Ultrasound (US) and thyroid scintigraphy are the primary imaging modalities used in clinical practice. This systematic review evaluates the diagnostic utility of US and thyroid scintigraphy in the management of TGDCs, comparing their diagnostic performance and assessing whether a combined imaging approach improves patient care. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies assessing the diagnostic roles of US and thyroid scintigraphy in TGDCs were identified through comprehensive searches of PubMed, Web of Science, Scopus, and ScienceDirect, with the final search conducted on May 5, 2024. A total of 18 studies involving 823 patients met the inclusion criteria. The results consistently showed that ultrasound is the preferred imaging modality, offering noninvasive, radiation-free, and highly accurate diagnostic capabilities. Ultrasound confirmed TGDC diagnosis in 66.1% of cases across studies, with detailed anatomical imaging supporting preoperative planning. Thyroid scintigraphy, while useful in cases of suspected ectopic thyroid tissue, was less frequently employed and generally unnecessary when a normal thyroid was identified on ultrasound. The Sistrunk procedure remains the preferred surgical intervention, with preoperative US proving essential in planning. Ultrasound is the most effective and noninvasive imaging tool for diagnosing TGDCs and planning preoperative interventions. Thyroid scintigraphy should be reserved for selected cases in which ectopic thyroid tissue is suspected. The findings support the use of ultrasound as the primary imaging modality, with thyroid scanning playing a secondary and more selective role in the management of TGDC.