Grain whisky is any whisky made from at least some grains other than barley, such as wheat and maize (corn). Some grain whisky also contain malted barley. (Whisky made from only barley is called malt whisky. This can be confusing: both malt whisky and grain whisky are made from grain malt.) The term is especially used in reference to Scotch whisky.

Grain whisky is typically distilled in a continuous column still, known as a patent or Coffey still, the latter after Aeneas Coffey who refined the column still in 1831.Due to

the higher alcohol yield from a patent still, grain whisky is generally accepted to have a lighter and less complex flavour than malt whisky, which is produced in a pot still. It nonetheless plays a very important role in the production of Scotch whisky as it is used to create blended whiskies.

In Scotland, pure grain whisky is seldom bottled and instead is manufactured explicitly for blending with malt whisky. Their comparative lightness is used to smooth out the often harsh characteristics of single malts. Occasionally well-aged grain whiskies are released as 'single grain whisky'. The best of these are almost indistiguishible in flavour from the best single malts.