Louis Gauchat (born 12 January 1866 in Les Brenets, Switzerland; died 22 August 1942 in Lenzerheide) was a Swiss linguist.

In 1899 he founded Glossaire des patois de la Suisse romande (Glossary of dialects of French-speaking Switzerland), an institution to publish studies of Switzerland's French dialects.

The institute receives subsidies from French-speaking cantons and the Swiss Confederation.

Jules Jeanjaquet and Ernest Tappolet assisted in phonetic survey work.

[3][4][5] His 1905 article on the vernacular of the Swiss village of Charmey is considered a precursor in the field of sociolinguistics.