Despite its existence for over six decades, the practice of human performance technology (HPT) has not been widely accepted within organizations. Varying levels of confusion surround the understanding of HPT, which has been influenced by myriad fields and disciplines. Although HPT is focused on improving performance at the organizational, team, and individual levels, it does not own the practice of performance improvement. The goal of optimal performance across various functions and levels within an organization is not confined to HPT but extends to process improvement, human resource development, organizational development, knowledge management, and several other areas. Therein lies the problem: A lack of consideration about the boundaries that delineates the field has ramifications for both the research on and the practice of HPT. This study examines the domains and disciplines that HPT proponents consider central to the field.