Mells Park is a country estate of 140 hectares (350 acres) near Mells, Somerset, England. It originated as a 17th-century deer park, probably created by the Horner family, who had been the owners of Mells Manor from 1543. The Horners expanded the park and planted extensive woodlands, resulting in a large collection of mature trees, especially 18th-century plantings of oak, lime and beech. The park is Grade II listed in the National Register of Historic Parks and Gardens. It contains Park House, also known as Mells Park House, a Grade II* listed building, built in 1925 in neoclassical style by the architect Edwin Lutyens, replacing an 18th-century house of the same name. It is c. 1 mile (1.6 km) west of Mells Manor House, which does not lie within the park.
During 1987–90, Park House was used for secret negotiations between the African National Congress and the South African government.
The estate is a venue for game shooting.
The deer park was enclosed between 1604 and 1642, probably by Sir John Horner. In 1724 Thomas Strangways Horner commissioned Nathaniel Ireson to build the first Park House, and the family moved there from Mells Manor House. His nephew Thomas Horner expanded the park and planted extensive woodlands, a work continued by his son Colonel Thomas Strangways Horner. The house is on high ground towards the northern end of the park, surrounded by river valleys. Further north, to the rear of the house, the park includes a lake fed by the Mells River. Pleasure grounds around the house and towards the lake were laid out by the landscape designer William Sawrey Gilpin between 1825 and 1832.
Future Prime Minister H. H. Asquith and his wife Margot spent their honeymoon at Mells Park in 1894, as guests of Sir John Horner and his wife Lady Frances Horner, the daughter of Liberal MP and art patron William Graham. Finding Park House too expensive to inhabit, in c. 1900 the Horners let it out and moved back into Mells Manor House. Park House burnt down in 1917, although an arcaded service court at the rear of the house survived.