In chemistry, pyran is a six-membered heterocyclic, non-aromatic ring, consisting of five carbon atoms and one oxygen atom and containing two double bonds.

There are two isomers of pyran that differ by the location of the double bonds.

Although the pyrans themselves have little significance in chemistry, many of their derivatives are important biological molecules, such as the pyranoflavonoids.

The term pyran is also often applied to the saturated ring analog, which is more properly referred to as tetrahydropyran (oxane).

In this context, the monosaccharides containing a six-membered ring system are known as pyranoses.