The Spanish hatchback was awarded the Eco Car of the Year title at the annual awards ahead of a host of other low-CO2 and frugal models.
Voted for by the Association of Scottish Motoring Writers, the Leon E Ecomotive was praised for its ultra-low CO2 emissions of just 99g/km – which enables the car to be exempt from UK road tax.
Fuel economy from the 105PS, 1.6-litre TDI engine is 74.3mpg, and the ‘E Ecomotive’ badge is used to signify the most efficient and frugal engines in the Leon range.
John Murdoch, President of the ASMW, said: "There is no complicated technology or heavy battery packs, just an efficient diesel engine and a variety of aerodynamic and mechanical tweaks.
"The result is exceptional. In real world driving conditions the Leon E Ecomotive is more economical than any of its direct rivals, while its keen pricing and exemption from road tax make it a sure-fire winner with canny Scots."
A second Leon model, the sporty Seat Leon Cupra R, was awarded the Sporting Car of the Year award for its headline performance figures.
These include a top speed of 155mph and a 0-62mph sprint time of 6.2 seconds from the 2.0-litre turbocharged petrol engine.
The car is Seat’s most powerful production car ever sold in the UK, and the judges said: "In various forms our winner is already a familiar sight on Scottish roads but, in the new flagship Cupra R guise, we believe it is the most thrilling and value for money hot hatch on sale today."
The Seat Leon E Ecomotive and Cupra R are on sale in the UK now.