Rupandehi District (Nepali: रुपन्देही जिल्ला; pronounced [ɾu.pʌn.de.i; -e.ɦi] ^ⓘ), a part of Lumbini Province, is one of the seventy-seven districts of Nepal and covers an area of 1,360 km² (530 sq mi). The district headquarter is Bhairahawa. As per the national census 2021, the population of Rupandehi was 1,118,975.

Rupandehi is named after Rupandevi temple which is situated in garden of Lumbini, where, the queen of King Suddhodana visited and give birth to Siddhartha Gautama Buddha.

Lumbini, birthplace of Buddha, lies in Rupandehi district. Devdaha, the birthplace of Mayadevi (mother of Buddha), also lies in Rupandehi district.

At the time of the 2021 Nepal census, Rupandehi District had a population of 1,121,957. 8.17% of the population is under 5 years of age. It has a literacy rate of 81.23% and a sex ratio of 1038 females per 1000 males. 656,483 (58.51%) lived in municipalities.

Bahun are the largest group, making up around 16% of the population. Magar are the second-largest group, making up 10.86% of the population.Tharus are 8%, while Muslims are 8% of the population.

At the time of the 2021 census, 42.57% of the population spoke Nepali, 31.83% Bhojpuri, 10.14% Awadhi, 7.27% Tharu, 4.13% Magar, 1.14% Urdu and 0.91% Gurung as their first language.

Rupandehi is divided into 16 local level units, in which 6 are urban municipality and 10 are Rural Municipality. Butwal is considered as a Sub-Metropolitan municipality.

Rupandehi is divided into 5 Parliamentary constituencies and 10 Provincial constituencies.