Grenchen (Swiss Standard German pronunciation: [ˈɡrɛnçn̩]; French: Granges [ɡʁɑ̃ʒ] ) is a municipality in the district of Lebern in the Canton of Solothurn in Switzerland.

It is located at the foot of the Jura Mountains between Solothurn and Biel/Bienne , approximately 25 km (16 mi) north of Bern . With over 16,000 inhabitants, it is one of the larger towns of the canton of Solothurn. The city is well known for its watch industry, that has been present for more than 150 years.

Grenchen was the 2008 winner of the Wakker Prize for architectural heritage.

Jura-Sternwarte Grenchen is located at Grenchen.