Despite progress in oncotherapy, cancer is still among the deadliest diseases in the Western world, emphasizing the demand for novel treatment avenues. Cold physical plasma has shown antitumor activity in experimental models of, e.g., glioblastoma, colorectal cancer, breast carcinoma, osteosarcoma, bladder cancer, and melanoma in vitro and in vivo. In addition, clinical case reports have demonstrated that physical plasma reduces the microbial contamination of severely infected tumor wounds and ulcerations, as is often seen with head and neck cancer patients. These antimicrobial and antitumor killing properties make physical plasma a promising tool for the treatment of head and neck cancer. Moreover, this type of cancer is easily accessible from the outside, facilitating the possibility of several rounds of topical gas plasma treatment of the same patient. Gas plasma treatment of head and neck cancer induces diverse effects via the deposition of a plethora of reactive oxygen and nitrogen species that mediate redox-biochemical processes, and ultimately, selective cancer cell death. The main advantage of medical gas plasma treatment in oncology is the lack of adverse events and significant side effects compared to other treatment modalities, such as surgical approaches, chemotherapeutics, and radiotherapy, making plasma treatment an attractive strategy for the adjuvant and palliative treatment of head and neck cancer. This review outlines the state of the art and progress in investigating physical plasma as a novel treatment modality in the therapy of head and neck squamous cell carcinoma.