The first Nepalese Constituent Assembly was a unicameral body of 601 members that served from May 28, 2008, to May 28, 2012. It was formed as a result of the first Constituent Assembly election held on April 10, 2008. The Constituent Assembly (CA) was tasked with writing a new constitution, and acting as the interim legislature for a term of two years. 240 members were elected in single-seat constituencies, 335 were elected through proportional representation, and the remaining 26 seats were reserved for nominated members.

Constituent Assembly elections were held in Nepal on 10 April 2008, having been postponed from earlier dates of 7 June 2007 and 22 November 2007. The Constituent Assembly was planned to draft a new constitution and therefore decide, amongst other things, on the issue of federalism. The number of eligible voters was around 17.5 million. The Constituent Assembly was originally set to have a term of two years.