Purpose The College of American Pathologists produced an evidence-based guideline on testing, application, interpretation, and reporting of human papillomavirus (HPV) and surrogate marker tests in head and neck carcinomas that was determined to be relevant to the American Society of Clinical Oncology (ASCO) membership. Methods The College of American Pathologists HPV Testing in Head and Neck Carcinomas guideline was reviewed by ASCO content experts for clinical accuracy and by methodologists for developmental rigor. On favorable review, an ASCO Expert Panel was convened to review the guideline contents and recommendations. Results The ASCO Expert Panel determined that the recommendations from the HPV Testing in Head and Neck Carcinomas guideline, published in 2018, are clear, thorough, and based upon the most relevant scientific evidence. ASCO endorsed the guideline and added minor qualifying statements. Recommendations It is recommended that HPV tumor status should be determined for newly diagnosed oropharyngeal squamous cell carcinomas. HPV tumor status testing may be performed by surrogate marker p16 immunohistochemistry either on the primary tumor or from cervical nodal metastases only if an oropharyngeal primary tumor is present. The threshold for positivity is at least 70% nuclear and cytoplasmic expression with at least moderate to strong intensity. Additional confirmatory testing may be done at the discretion of the pathologist and/or treating clinician. Pathologists should not routinely determine HPV tumor status in nonsquamous carcinomas of the oropharynx or non- oropharyngeal squamous cell carcinomas of the head and neck. When there is uncertainty of histologic type or whether a poorly differentiated oropharyngeal tumor is nonsquamous, HPV tumor status testing may be warranted and at the discretion of the pathologist and/or treating clinician. Additional information is available at: www.asco.org/head-neck-cancer-guidelines.