Head and neck squamous cell carcinoma (HNSCC) is a malignancy with a high incidence and significant therapeutic challenges, contributing to substantial mortality worldwide. The current standard treatment modalities for HNSCC include surgical resection, radiotherapy, and chemotherapy. However, the long-term efficacy of these approaches remains limited, especially in advanced stages. Immunotherapy, particularly immune checkpoint inhibitors, has emerged as a novel therapeutic strategy, showing considerable promise in treating HNSCC. More recently, the combination of immunotherapy and radiotherapy, known as immunoradiotherapy (iRT), has attracted significant attention due to its potential to enhance anti-tumor effects through synergistic mechanisms. This review outlines the epidemiology and disease burden of HNSCC, discusses the evolution of radiotherapy and immunotherapy, and examines their application in the treatment of HNSCC. Furthermore, we explore the underlying biological mechanisms of iRT, including its ability to modulate the tumor microenvironment and enhance immune-mediated tumor cell killing. The current landscape of clinical trials investigating iRT in HNSCC is also reviewed, along with the potential role of adjunctive therapies to improve treatment outcomes. Lastly, we discuss the future prospects of iRT in HNSCC, highlighting its potential to improve patient survival and reduce recurrence rates, thereby offering a more effective therapeutic strategy for this challenging malignancy.