This article examines the function of the Senate of Pakistan as the guardian of provincial interests from 1985 to 1999, evaluating its impact and efficacy within the framework of federal governance. The Senate's role as a representative institution for provinces, designed to guarantee equitable regional representation and protect provincial rights, is thoroughly examined by analyzing significant legislative events and political dynamics of the era. This study emphasizes the Senate's role in influencing national policies, specifically in regards to federal-provincial relations, fiscal federalism, and regional autonomy. The essay assesses the Senate's effectiveness in safeguarding province interests in the face of changing political dynamics and institutional obstacles by using analytical method of research and analyzes Senate debates, committee activities, and legislative outcomes. The findings suggest that although the Senate had a crucial role in representing the voices of the provinces, its ability to make an impact was frequently hindered by political disagreements, structural deficiencies, and the wider context of national governance problems. The essay offers an analysis of the Senate's capabilities and constraints as a guardian of provincial interests, and proposes suggestions for improving its position within Pakistan's federal structure.