Gais is a village and a municipality in the canton of Appenzell Ausserrhoden in Switzerland. The area of Gais is 21.21 km2 (8.19 sq mi).

Appenzell Ausserrhoden, in English sometimes Appenzell Outer Rhodes, is one of the 26 cantons forming the Swiss Confederation. It is composed of twenty municipalities. The seat of the government and parliament is Herisau, and the seat of judicial authorities are in Trogen. It is traditionally considered a "half-canton", the other half being Appenzell Innerrhoden.