Kapilvastu 1 one of three parliamentary constituencies of Kapilvastu District in Nepal.

This constituency came into existence on the Constituency Delimitation Commission (CDC) report submitted on 31 August 2017.

[1] Kapilvastu 1 incorporates Suddhodhan Rural Municipality, Mayadevi Rural Municipality, Banganga Municipality and wards 8–11 of Kapilvastu Municipality.

It encompasses the following Lumbini Provincial Assembly segment