Diols have exactly two alcohol groups. Diols are common monomers used in copolymers.

In polymer chemistry, "polyol" can also mean polymer diols with an −OH group at each end of a long chain, even if most of the chain does not have those groups.

Triols have three alcohol groups. The most important triol is glycerol. Most plant and animal fats are triglyceride esters related to glycerol. Another important triol is epinephrine.

A sugar alcohol is a polyol that has an alcohol group on every carbon atom. Sugar alcohols are a type of carbohydrate.