Sembrancher (French pronunciation: [sɑ̃bʁɑ̃ʃe]) is a municipality in the district of Entremont in the canton of Valais in Switzerland .

Sembrancher is first mentioned in 1177 as Sancti Pancratii de Branchi. Its German name St Branschier is no longer used.

Sembrancher has an area, as of 2011, of 17.7 square kilometers (6.8 sq mi). Of this area, 17.5% is used for agricultural purposes, while 63.1% is forested. Of the rest of the land, 4.1% is settled (buildings or roads) and 15.3% is unproductive land.