In each country, each different political institution will have different legal regulations on the supervision of Parliamentarians in the settlement of their citizens' complaints and denunciations. In Vietnam, the supervision of Parliamentarians for the settlement of citizens' complaints and denunciations still faces many difficulties, inadequacies and limitations. Therefore, the authors have studied the Parliamentarians' supervision for citizens' complaints and denunciations in some countries around the world. Thereby, draw some lessons and experiences for Vietnamese Parliamentarians in supervising the settlement of citizens' complaints and denunciations in the future. In order to promote the competent authorities to obey the law and better serve organizations and individuals, upholding the spirit of rule of law. At the same time, contribute to improve the prestige and professionalism of the National Assembly, the Standing Committee of the National Assembly, and the Parliamentarians in the people's asprirations; strengthen the close relationship between the National Assembly, the Standing Committee of the National Assembly and voters, People.