Grub AR is a municipality in the canton of Appenzell Ausserrhoden in Switzerland.

Of the rest of the land, 12.8% is settled (buildings or roads) and the remainder (0.2%) is non-productive (rivers, glaciers or mountains).

It consists of the village of Grub and scattered hamlets and individual farm houses.

Most of the population (as of 2000[update]) speaks German (94.4%), with Spanish being second most common ( 1.0%) and Italian being third ( 0.5%).

[6] The age distribution, as of 2000[update], in Grub is; 90 people or 8.7% of the population are between 0–6 years old.