The 50-megawatt scheme is set to be built on a former military airfield in the northeast of Scotland after planning consent was granted by Scottish ministers.
It will include 200,000 solar panels and will supply enough green energy to power up to 15,000 homes or 19,000 electric vehicles each year once operational.
The massive development will occupy around 115 hectares, the equivalent of around 140 football pitches, at Milltown Airfield, near Elgin in Moray.
It is the first solar development approved by the Energy Consents Unit (ECU) of the Scottish Government, which rules on projects of 50 megawatts or greater in output.
The ECU has allowed a five-year timescale for commencement of the project owing to its “scale and complexity”.
The former RAF airfield was decommissioned in the 1970s and since then has been used for a variety of activities, including storage, truck testing and livestock grazing.
Sheep will continue to be kept at the site, which belongs to Innes Estate, once construction is complete.
Edward Tennant, who owns the estate and 350-year-old Innes House, said: “This is an exciting new chapter for Innes Estate. For 20 years my parents have grown and diversified the business to span from farming and forestry to weddings and corporate entertainment.
“This new project will provide yet more diversification, and most importantly it will allow us to re-invest in one of Morayshire’s most important historic houses.
“The need for renewable energy is becoming increasingly important and we are very happy to be contributing to the green future of Scotland.”
Bristol-based firm Elgin Energy is behind the project.
The developer has a number of other Scottish project in the pipeline, including a 20 megawatt project near Urquhart, also on the Innes Estate.
It also created Scotland’s largest operational solar farm, a 13-megawatt project at Errol Estate in Perthshire, which went live in May last year.
Environmentalists and green businesses have welcomed the ECU decision.
Dr Sam Gardner, acting director of WWF Scotland, said: “After many parts of Scotland have been basking in sunshine over recent days, it’s great to see this large solar farm granted planning permission.
“Solar will have an important role to play in helping Scotland reach its 50 per cent renewable target by 2030.
“It’s low-cost, popular with the public and is playing an increasingly important role UK wide in helping to keep the lights on.”
Stephanie Conesa, policy manager at industry body Scottish Renewables, said: “It will surprise many that the electricity generation potential of a solar PV array in Scotland is very similar to, if not better than, in central or northern England or parts of Wales.
“Scotland really can be a hotspot for this type of green energy.”