Introduction: To review outcomes of patients treated with radiotherapy (RT) for T4 non‐melanoma skin cancer (NMSC). Methods: A retrospective chart review was performed of 21 patients who received RT for T4 NMSC from 2004 to 2010. Outcomes of treatment efficacy, RT technique and patient morbidity were analysed. Twelve patients (57.1%) were treated definitively without prior treatment, five (23.8%) were recurrent lesions and four (19.1%) were treated postoperatively. Ten patients (47.6%) had evidence of bony erosion at presentation, and four (19.1%) had nodal disease. Intensity‐modulated radiotherapy (IMRT), three‐dimensional conformal RT and electron treatment were included RT techniques. Results: Median follow‐up was 12 months (range, 5–48 months). Twelve patients (57.1%) following RT required no further treatment and had no disease recurrence. Three patients (14.3%) required salvage treatment and are disease‐free following all treatment. Tumours treated initially or postoperatively had improved control rates following RT compared with recurrent lesions (58.3% and 100% vs. 20%). Sixty percent of patients treated with IMRT achieved local control following RT, and 80% were disease‐free following surgical salvage treatment. Squamous cell carcinoma (SCC) histology, presence of bony erosion and/or nodal disease was associated with a higher incidence of disease recurrence. Conclusions: Patients presenting with untreated lesions, smaller tumour volumes (<70 cm3) postoperatively, basal cell histology and absence of bone erosion or nodal disease have improved local control and outcomes. Basal cell carcinoma and SCC should be staged and treated as two separate disease entities. The use of IMRT for advanced skin cancer warrants further investigation.