Glassine is a very thin and smooth type of paper which is air and water resistant. It is generally translucent unless dyes are added to color the paper or make it opaque.

Glassine has a number of practical uses. It is frequently employed as an interleaving paper in bookbinding, especially for illustrations; the paper can be manufactured with a neutral pH, and can prevent damage from spilling, exposure, or rubbing. Glassine tape has also been used in book repair. In chemistry, glassine is used as an inexpensive weighing paper. It is also used in foodservice as a barrier between strips of products; glassine is resistant to grease and facilitates separation of individual foodstuffs.