As a branch of the government, the judiciary plays a crucial role in guaranteeing that, in a democracy, the principle of separation of powers is rigorously upheld. Like other democratic governments worldwide, Nigeria's 1999 Constitution upholds the principle of
separation of powers, which greatly influences how well a nation is run. Once again, the judicial branch is a crucial political institution because of its many functions, which are rooted in the rule of law, and safeguard a democratic government to remain viable.
However, the judiciary's numerous transgressions, which range from open corruption to inadequate case management, have rendered it weak. This paper examines the judiciary's role as a branch of government in upholding Nigeria's theory of separation of powers using secondary data. It determines that the rigorous adherence to the theory has not been upheld by the judiciary. It, therefore recommends that, among others, the implementation of the 1999 Constitution's Section 121(3) that ensures the heads of the courts receive payment from the Consolidated Revenue Fund of the State for any sum standing to the credit of the judiciary, members of the Executive and Legislative branches who violate the 1999 Constitution's provision on the financial autonomy of the Judiciary as reflected in Section 121 (3) be subject to jail time as a criminal penalty. Also, the states should not be involved in the financing of capital projects at state high courts and their subsidiaries to break the governors' control over these entities.