The project in Caithness, which had been reduced from eight turbines to five, was turned down by the Highland Council under delegated powers.
The refusal came despite the fact the site lies within an area identified by the Highland Council as having “potential for wind farm development”.
The wind farm would have been located approximately 4.5km west of Thurso.
The proposed scheme also included measures to enrich key habitats across the site and achieve a 16% biodiversity net gain.
RES development project manager Euan Hogg said: “We carefully considered the council’s feedback on our previous eight-turbine proposal and significantly reduced the scheme in response to this, so we’re naturally disappointed by the refusal – particularly given the importance of projects like Cairnmore Hill amidst the climate change emergency we are facing.
“This project could deliver significant inward investment to the area in addition to playing an important part in helping meet Scotland’s net zero carbon targets.
“Community support for the project has also been shown with over 200 support letters submitted into planning.
“We will now take time to review the council’s decision and consider our options for the site.”
If consented, the scheme was predicted to deliver around £1.4m of inward investment in the form of jobs, employment and the use of local services as well as £8.75m in business rates to the Highland Council over the wind farm’s operational lifetime.
The site’s closest resident James Mackay, of Forss, said: “Highland Council’s refusal doesn’t make any sense.
“It’s a great location for a wind farm, the wind never stops blowing. Their decision means that we’re missing out on local construction jobs and contracts as well as much-needed funding for community groups in Forss and Thurso.
“It would have given the area a boost, so it’s a real shame it’s not gone through.”
RES had also committed to providing a tailored package of benefits aligned with local community priorities.
The developer said Cairnmore Hill would have been capable of generating enough clean, low-cost electricity to meet the annual demand of around 28,000 homes and offsetting approximately 23,736 tonnes of carbon emissions compared to the use of fossil fuels.