18F-fludeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) has been performed widely in diagnosis and management of patients with oropharyngeal squamous cell carcinoma (OPSCC). This review summarizes the literature on this tool in the management of these patients. The use of FDG-PET/CT helps in accurate staging of primary tumor, nodal involvement, and distant metastasis of patients with OPSCC. Contrast-enhanced FDG-PET/CT combines high-resolution CT and functional FDG-PET, providing the optimum imaging information for patient management. Using contrast-enhanced PET/CT leads to a combined anatomic and metabolic approach to radiation therapy planning in OPSCC. Moreover, PET/CT not only is a good modality for therapy assessment but also is a powerful tool in early recurrence detection of OPSCC. Finally, the PET/CT parameters provide survival information in patients with OPSCC; however, further studies are needed to introduce a scoring system to use clinically for prognosis prediction.