Key Points 1. This study reports clinical outcome data on 76 patients with platinum-resistant recurrent or metastatic head and neck squamous carcinoma treated with nivolumab, making it the largest published single centre case series of its kind. 2. Radiotherapy was administered alongside systemic therapy with nivolumab, defined as radiotherapy within 8 weeks of prior systemic therapy, in 16 of 76 patients (21%). 3. Nivolumab was continued following radiotherapy completion due to ongoing clinical benefit from the drug in 9 of 16 patients (56%). 4. Durable complete response following radio-immunotherapy was seen in 2 of the 9 patients (22%) who continued nivolumab subsequent to radiotherapy. 5. Indications for radiotherapy included symptom control (3 of 9), oligoprogression (5 of 9) and incomplete response (1 of 9).