The mission of the Division of AIDS (DAIDS), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), is to increase basic knowledge of the pathogenesis and transmission of the human immunodeficiency virus (HIV), support the development of therapies for HIV infection and its complications, and support the development of vaccines and other prevention strategies. Reliable laboratory data are essential to the clinical evaluation of candidate HIV vaccine platforms and immunogens. Data from multiple laboratories performing assays in support of single or multiple vaccine candidate trials must be accurate and reproducible. The purpose of the External Quality Assurance Program Oversight Laboratory (EQAPOL) is to provide confidence that individual laboratories generate reliable data to support HIV vaccine immunogen advancement. EQAPOL supports these efforts by participating in the development and availability of validated assays, providing common and well-characterized reagents and Standard Operating Procedures (SOPs), and providing External Quality Assurance (EQA) programs to measure and monitor laboratory performance.