The National Assembly of the Republic of South Sudan was established through Presidential Decree No. 10/2011 for the Reconstitution of the National Legislative Assembly of the Republic of South Sudan, 2011 issued on 1 August 2011.

It replaced the Southern Sudan Legislative Assembly (SSLA) which came to existence under Art. 57 (1) of the Interim Constitution of the Southern Sudan 2005, as provided for in the Comprehensive Peace Agreement (CPA) signed between the Sudan Government and the Sudan People Liberation Movement (SPLM) in Naivasha – Kenya on 9th January 2005. The SSLA was originally composed of 70% SPLM members, 15% NCP members, and the other political parties make up the 15% as stipulated by the CPA.

However, following the April 2010 general elections, members of the SSLA were either elected or nominated as per the Constitution. The Presidential Decree establishing the National Legislative Assembly also reconstituted its membership. Now it is composed of all the members of the former SSLA, former members of the National Legislative Assembly of the Republic of Sudan elected from constituencies in Southern Sudan, and members appointed under Article 94(2)(b) of the Transitional Constitution of South Sudan.

The National Legislative Assembly exercises the following functions:

1. overseeing the performance of the National Government institutions;
2. approving plans, programmes and policies of the National Government;
3. approving budgets;
4. ratifying international treaties, conventions and agreements;
5. adopting resolutions on matters of public concern;
6. summoning Ministers to answer questions of members of the Assembly on matters related to their ministries;
7. interrogating Ministers about their performance or the performance of their ministries;
8. approving appointments as required by the Transitional Constitution or the law;
9. casting a vote of no confidence against the Vice President and any Minister;
10. enacting legislation to regulate the conditions and terms of service of the Judiciary and its oversight mechanisms; and
11. performing any other function as determined by the Transitional Constitution or the law.