Demi-Sec, literally "half-dry" is a term used in Champagne. Although called half-dry, a demi-sec Champagne is medium sweet, as it is legally defined as having between 33 to 50 grams of residual sugar. Thus a demi-sec is too sweet for the dinner table, but works well with pastries and cakes.

Once popular, it has declined in sales, as consumers prefer drier Champagnes.