Zinc finger MYM-type protein 3 is a protein that in humans is encoded by the ZMYM3 gene.

This gene is located on the X chromosome and is subject to X inactivation. It is highly conserved in vertebrates and most abundantly expressed in the brain. The encoded protein is a component of histone deacetylase-containing multiprotein complexes that function through modifying chromatin structure to keep genes silent. A chromosomal translocation (X;13) involving this gene is associated with X-linked mental retardation. Several alternatively spliced transcript variants have been found for this gene. [provided by RefSeq].