Background: With results of chemo-radiotherapy de-escalation trials for Human Papillomavirus (HPV)-associated oropharyngeal carcinoma (OPC) pending, any reduction in toxicity may be offset by the increased need for post-therapy neck dissection (PT-ND) for suspected residual nodal disease. We report the rate of PT-ND and overall regional failure rate following standard radiotherapy (RT) with or without chemotherapy (chemo)RT in node positive HPV-associated OPC. Secondary objectives include estimated 5-year regional failure free survival (FFS), loco-regional FFS, distant metastatic FFS and overall survival (OS). Methods: Patients treated between Jan 2005-Jan 2016 on a pre-defined (chemo)RT protocol and 12-week restaging PET/CT (treatment package) with a minimum of 18 months follow up (FU) were analysed. Patients receiving concurrent chemo were prescribed high-dose cisplatin and 70Gy/7 weeks to gross disease. Those ineligible for cisplatin received weekly cetuximab. PT-ND was performed if residual nodal disease was suspected on the restaging scan with complete response at the primary site and no evidence of distant disease. Results: 343 patients were eligible. Median follow up was 60 months, with 302 (88%) alive at the close-out date. Median age was 59 (range, 21-89) yrs. The predominant AJCC/UICC 7^th Edition (Ed) T- & N-stage were T2 (37.3%) & N2b (44.9%), respectively. The 8^th Ed group staging were; Stage I-49%, Stage II-28% & Stage III–23%. Median RT dose was 70Gy (range, 66-70Gy) and 336 (95.6%) received systemic therapy. At the completion of the treatment package 4.6% (16pts) underwent a ND. 10 pts (62.5%) were pathologically positive. The overall regional failure rate was 6.4%. The estimated 5-year regional FFS was 93% (95% CI: 90.2-95.9), loco-regional FFS 90.6% (95% CI: 87.3-94.0) and distant metastatic FFS 86.9% (95% CI: 83.1-90.8). 5-year OS by stage were; I–93.4% (95% CI: 89.5-97.5), II–82.9% (95% CI: 75.3-91.3) & III–75.9% (95% CI: 66-87.3). Conclusions: Following the treatment package the ND rate was low and regional failure uncommon. These findings serve as a benchmark to assess the benefit of de-escalation trials, which may be offset by an increased need for PT-ND.