Abstract We analyzed the inclusion of sex and/or gender (S/G) in Head and Neck Cancer (HNC) clinical studies, through inspecting ClinicalTrials.gov (AACT) and the mention of Human Papilloma Virus (HPV) on a specific subgroup, namely oral cavity, larynx and oropharynx. Only 5% of HNC studies mention S/G as a planned analytical variable. Proportionally more observational studies treated S/G as an analytical variable than interventional studies (10% vs 5%, P-value ≤ 0.001), 8% of studies that mentioned S/G involved more than 100 subjects while 4% less than 100 (P-value ≤ 0.001). In randomized protocols, S/G was mentioned more in studies with a planned sample of more than 100 patients and including HPV status (P-value