Microstomia (from Greek micro- 'small' and -stomia 'mouth') is the medical condition of an abnormally small mouth.

It may present with whistling-face feature, as well, as in Freeman-Sheldon syndrome.

In this syndrome, it impairs alimentation and may require repeated oral surgeries (called commissurotomy) to improve function.

[citation needed] Microstomia can occur as a result of scarring due to many conditions.

It is seen as complication of facial burns.