An application had been submitted to build a 50m turbine with ancillary equipment at Bryony Hill Farm in Winkleigh, Devon, but it was rejected by Torridge District Council.
The applicant appealed, but the decision has been upheld by a planning inspector.
The planning inspector ruled that the harm identified to the setting of important heritage assets, the qualities of the landscape and to living conditions substantially outweighed the benefits of the proposal.
Penny Mills, chairman of CPRE Devon, said: "This wind turbine in the beautiful 'Warhorse valley' quite clearly did not have the support of the majority of local people, as the overwhelming majority objected to it.
"This proposal has been like a dark cloud hanging over the area for a very long time - it's two years since the screening opinion was first submitted, so this decision is a great relief."