Histone deacetylase 1 (HDAC1) is an enzyme that in humans is encoded by the HDAC1 gene.

Histone acetylation and deacetylation, catalyzed by multisubunit complexes, play a key role in the regulation of eukaryotic gene expression. The protein encoded by this gene belongs to the histone deacetylase/acuc/apha family and is a component of the histone deacetylase complex. It also interacts with retinoblastoma tumor-suppressor protein and this complex is a key element in the control of cell proliferation and differentiation. Together with metastasis-associated protein-2 MTA2, it deacetylates p53 and modulates its effect on cell growth and apoptosis.

HDAC1 has been shown to interact with: