Jenever, juniper-flavored and strongly alcoholic, is the traditional liquor in the Netherlands and Flanders, from which modern gin has evolved. Believed to have been invented by a Dutch chemist and alchemist named Sylvius de Bouve (or Franciscus Sylvius), it was first sold as a medicine in the late 16th century. In the 17th century it began to be popular for its flavor. Traditional jenever is still very popular in the Netherlands and Flanders. European Union regulations specify that only liquor made in these 2 areas can use the name jenever.

Jenever was originally produced by distilling maltwine (moutwijn in dutch) to 50% ABV. Because the alcohol didn't taste very nice due to lack of refined distilling techniques, only the pott still was available, herbs were added to enhance the flavour. The juniper berry (Jeneverbes in Dutch, which comes – in its turn - from the French Genievre) was best for that, hence the name Jenever. And the name Gin.

There are two types of Jenever: ‘Oude’ (Old) and ‘Jonge’ (Young). This is not a matter of aging, but of distilling techniques. Around 1900 it was technically possible to distill an almost neutral high graded type of alcohol, in taste even independent of the origin of the spirit. A worldwide tendency for a lighter and less outspoken taste, and lower prices, led to blended whisky in Great Britain, and in the Netherlands to Jonge Jenever. During the Great War, lack of imported cereals and hence malt, forced the promotion of this blend. Alchohol from molasses from the beet-sugar industry was an acceptable alternative for grainspirit. People started using the term ‘Oude’ for the old-style Jenever and ‘Jonge’ for the new style Jenever. The new style contains more grain instead of malt and can even contain plain sugar-based alcohol. It is written on the label when only grain and malt has been used (then it's called Graanjenever).

Korenwijn is a drink very similar to the 18th century style Jenever, and is often matured for a few years in an oak cask.

Hasselt, Belgium and Schiedam, the Netherlands are famous for their jenever.