The Valais (French pronunciation: [valɛ]; German: Wallis, German pronunciation: [ˈvalɪs] ( listen)) is one of the 26 cantons of Switzerland in the southwestern part of the country, around the valley of the Rhône from its headwaters to Lake Geneva, separating the Pennine Alps from the Bernese Alps. The canton is one of the drier parts of Switzerland in its central Rhône valley. Paradoxically, it is also one of most well-watered parts, having large amounts of snow and rain up on the highest peaks found in Switzerland. The canton of Valais is probably best known for the Matterhorn and ski resorts such as Zermatt and Verbier.

The Romans called the upper Rhône valley Vallis Poenina. The Vallis Poenina was won by the Romans after a great fight at Octodurus (Martigny) in 57 B.C., and was so thoroughly Romanized that both the Celtic original inhabitants and the Germanic Burgundian invaders of the 5th century, became romance language-speaking peoples. According to a tradition which can be traced back to the middle of the 8th century, the Theban legion was martyred at Agaunum (now Saint Maurice) about 285 or 302. From 888 onwards the lands were part of the kingdom of Jurane Burgundy.

The Suisse romande (lit.:"Romance Switzerland") is a local name for the French-speaking districts of western Switzerland. The name Romandie (Romandy) is also used. (Note that in French the word "romande" is an adjective and is not capitalised.) The term "Suisse romand" is used to refer to Swiss French, the variety of French spoken in Switzerland. There are about 1.6 million French-speakers in Switzerland, about 20% of the total population.

The word "romand/romande" indicates the Latin or Roman origin of the French language and the general orientation of the region to the French-speaking cultural sphere and to Roman Law. It is used in contrast to "Suisse alémanique" (German Switzerland) and "Suisse italienne" (Italian Switzerland).

The Suisse romande is not a precisely defined area, but in general includes the Cantons of Fribourg, Geneva, Jura, Neuchâtel, western Valais, Vaud and the northern part of Berne (known as the Jura Bienne or the Bernese Jura). The city of Geneva constitutes the largest urban area of the region.