Background: The MD Anderson Dysphagia Inventory (MDADI) is a widely used patient-reported outcome measure (PROM) which assesses dysphagia-related quality of life (QoL) in head and neck cancer (HNC). Despite its common use in HNC research and clinical practice, few of its psychometric properties have been reappraised since its inception. The aim of this study was to perform a survey-based qualitative analysis of UK HNC clinicians' perceptions of the content validity of the MDADI, evaluating it across the parameters of relevance, comprehensiveness and comprehensibility as per the COSMIN guideline for PROM assessment. Results: Four themes relating to the content validity of the MDADI were identified: (1) MDADI items lack clarity of definition of the terms 'swallowing', 'eating' and 'dysphagia'; (2) the MDADI is perceived to be overly negative in tone including items that service users may find distressing or disempowering; (3) items in the tool are exclusory to specific subgroups of patients, such as those who are nil by mouth or socially isolated; and (4) modifications to the MDADI were suggested and encouraged to make it more clinically useful and patient-centred. Conclusions: This study indicates that MDADI's content validity is 'insufficient' when rated by COSMIN parameters. This has significant implications for its continued use in HNC research and clinical practice. Further re-evaluation of the content validity of the MDADI is warranted, with potential future amendment of items being indicated if the results of this study are corroborated in subsequent research.