In 2015, the Sanghiya Sadbhawna Party, led by Anil Kumar Jha, merged with the Nepal Sadbhawana Party. Anil Kumar Jha became the chair of the integrated party, while Sarita Giri became the vice chairperson and Rajeev Jha became the General Secretary. In early October 2015, Sarita Giri quit the Nepal Sadbhawana Party. Later Nepal Sadbhawana Party merged with another four smaller parties: Madhesh Rastra Jantantrik Party (Krantikari), Social Republican Party, Nepal Republican People's Party and Jantantrik Terai Madhesh Mukti Tigers. Other local political leaders from Madhesh, from different parties in Mahottari, Bara and Rupandehi, also joined NSP. Following unification the party celebrated its silver jubilee, and participated in relief distribution after the devastating earthquake in Nepal. NSP's 6th General Convention in Janakpur took place in April 2016.