HD 1, also known as HIP 422, is a star in the Henry Draper Catalogue.
HD1 or HD 1 may also refer to:
- HD1, the oldest and most distant known galaxy yet identified in the observable universe.
- Plectin, a giant protein found in mammalian cells, for which HD1 is an alias.
- TF1 Séries Films, formerly known as HD1.