Improved prognosis for HPV-related oropharyngeal squamous cell carcinoma (OPSCC) has led to efforts to mitigate the potential long-term complications of head and neck radiation. Swallowing dysfunction impacts quality of life, and very late dysphagia at two years or beyond remains poorly defined. We sought to assess very late dysphagia in a cohort of OPSCC patients who underwent uniform IMRT chemoradiation on prospective institutional trials 2004-2011. Retrospective chart review was performed of 93 HPV+ OPSCC patients and scoring of video fluoroscopic swallow studies (VFSS) of patients was performed according to the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) scale for all available VFSS. End of treatment (EOT) was defined as the last day of radiation. Fine-Gray subdistribution hazards model was used to assess late dysphagia with competing risk of death. A linear mixed model was used to analyze the longitudinal change of score over time. Machine learning model using Random Forest with five-fold cross validation was used to assess the strongest predictors of two-year DIGEST score ≥ 2. All dosimetric hazard ratios (HR) were per 1 Gy increase. In an initial cohort of 93 patients, 24 have died, and 33 have been seen in our multi-disciplinary head and neck oncology program within the past 12 mo. Total median follow up was 10.5 years. 402 total VFSS were assessed (median 4 per patient, range 0-8). Patients underwent VFSS mandated on clinical trial at baseline (N=92), 3 mos (N=90), 12 mos (N=82) and 24 mos (N=75). After 2.5 yrs from EOT, VFSS were clinically driven and 39 studies were performed. Overall, 26.8% (22 of 82), 26.7% (20 of 75), and 69.2% (27 of 39) of VFSS had a DIGEST score 2 or higher at one, two, and greater than 2.5 years after EOT. Factors that significantly correlated with a clinically driven late DIGEST score of ≥2 included T-stage (HR 1.7, p=0.049), second head/neck cancer (HR 6.5, p=0.004), total pharyngeal constrictor dose (HR 1.08, p=0.049), superior pharyngeal constrictor mean dose (HR 1.11, p=0.050), inferior pharyngeal constrictor mean dose (HR 1.04, p=0.049), oral cavity mean dose (HR 1.06, p=0.033), and total tongue dose (HR 1.07, p=0.045) with smoking pack years being marginally significant (HR 1.01 p=0.053). The only pre-treatment factor significant for change in DIGEST score after EOT was baseline DIGEST score. Using a machine learning model, the mean dose to the superior constrictor was the strongest predictor of two-year DIGEST score ≥2, with a specificity of 89.1% and negative predictive value of 84%. Pre-treatment and treatment factors predict for the incidence of dysphagia. Very late dysphagia ≥ 2 years after head and neck cancer radiation remains incompletely characterized, without clear guidelines for long-term follow up of patients. These findings identify markers of very late dysphagia that may be incorporated into individualized survivorship guidelines.