This manual describes the Human-Animal Interaction Scale (HAIS), a self-report instrument designed to measure interactions between humans and animals. This manual describes the HAIS development and its psychometric properties, as well as its use, administration, scoring, and interpretation. It also includes forms for administering the HAIS. The HAIS has broad applicability; it can be used in a variety of settings (e.g., research, animal-assisted therapies and activities, animal sheltering and advocacy) and with a variety of species (e.g., companion animals, small caged animals, large pets or farm animals).