Gaster

Gaster may refer to:


 * Stomach (Greek: Gaster)
 * Gaster (insect anatomy)
 * a trade name of famotidine, an inhibitor of stomach acid production
 * W. D. Gaster, a character from the video game Undertale.
 * Gaster (surname)
 * Gaster, a character in the television series PaRappa the Rapper
 * Gaster (district), a constituency in St. Gallen, Switzerland