Estrogen-related receptor beta (ERR-β), also known as NR3B2 (nuclear receptor subfamily 3, group B, member 2), is a nuclear receptor that in humans is encoded by the ESRRB (EStrogen Related Receptor Beta) gene .
This gene encodes a protein with sequence similarity to the estrogen receptor, a member of nuclear hormone receptor family of steroid hormone receptors. Its function is unknown; however, a similar protein in mouse plays an essential role in placental development.