It was started as a breakaway faction of the Rastriya Prajatantra Party under leadership of Kamal Thapa, home minister under King Gyanendra's direct rule. Thapa resigned as party chair in October 2006. RPP won the largest number of mayors in the 2006 municipal election. Rajaram Shrestha won in the capital Kathmandu; also Khadga Prasad Palungua in Dharan, Pralhad Prasad Shah Haluwai in Biratnagar, Ram Shankar Shah in Jaleswor, Sumitra Madhinne in Bhaktapur, Madhukar Prasad Adhikari in Hetauda, Bimal Prasad Shrivastav in Birgunj, Bidur Khadka in Baglung and Bhimsen Thapa in Pokhara. However this election was boycotted by most major parties. In April 2006, the Nepal Samata Party merged into the party. In January 2007 the splinter group Rastriya Prajatantra Party of Rajeswor Devkota rejoined the party. Bidwai Parishad of Jit Bahadur Arjel also merged with them On March 2, 2008, Rabindra Nath Sharma stepped down as party chairman, citing health reasons. Kamal Thapa again became chairman.
Constituent Assembly, 2008-2015
The party won four seats in the 2008 Constituent Assembly election. At the first meeting of the Constituent Assembly on May 28, 2008, the party was the only party to oppose the declaration of a republic; there were 560 votes in favor of a republic and only the party's four votes against. Thapa subsequently said on June 20, 2008 that the country faced an impending "disaster", urging alertness among the party. He said that the party's policies and programmes would remain the same despite the political change. On July 13, 2008, he described the abolition of the monarchy as merely "an interim decision", saying that the party sought the restoration of the monarchy. The party boycotted the July 2008 presidential election in the Constituent Assembly, on the grounds that the major parties were treating the election as a partisan contest. In August 2008 some senior leaders, including Rabindra Nath Sharma and Rajeshwor Devkota, left the party and joined the Rastriya Prajatantra Party. The party won 24 seats under proportional representation in the 2013 Constituent Assembly elections making it the fourth largest party in the house. The party split following differences over naming candidates to the proportional representation seats won by the party. Central leaders of the party including former minister Tanka Dhakal and former Kathmandu mayoral candidate Rajaram Shrestha registered a new party the 'Nepali Rastriya Prajatantra Party' at the Election Commission on 30 December 2013. However, the Election Commission turned down the breakaway group's request seeking recognition as a new party and claim of proportional representation seats. Tanka Dhakal later announced his return to the party stating "Splitting the party at this moment is not in our interest. It will weaken democracy" Other dissidents leaders said it was Chairman Kamal Thapa's "concession on monarchy and Hindu state" that precipitated the split.
Unification, 2015-2016
When the party joined the government of Khadga Prasad Oli, Bikram Bahadur Thapa and Kunti Devi Shahi became state ministers. On 21 November 2016, Rastriya Prajatantra Party Nepal and Rastriya Prajtantra Party announced their unification. The new party retained the name of Rastriya Prajatantra Party. The new party had a total strength of 37 in the Parliament of Nepal becoming the fourth largest party. Kamal Thapa was elected chairman of the party in a special general convention in Kathmandu on February 2017.
