With the setting in of the Fourth Republic as from May 29, 1999, under a civil democratic presidential system, expectations were high with regard to the effective utilization of Nigeria’s foreign policy for reaping greater benefits through its economic relations instrument. However, over twenty-four years into one of the longest civilian administration in the country’s history, our main external revenue sources still remains Oil & Gas (O&G). Nigeria as an aspirant to the group of 20 most developed countries of the world at the lapsed dateline of 2020 without any visible means of taking-off as at today(2023); must have to expand its foreign revenue sources and where possible, move it away from O&G to industrialization and manufacturing. This is based on the fact that O&G apart from being an exhaustible foreign revenue sources; often encounters abrupt drop in price at the international market due to unforeseeable oil glut or even lack of market (sales) due to natural disasters and calamities such as the COVID-19 pandemic. The study is a qualitative one where document studies was adopted for generating data through secondary sources such as textbooks, academic journals, magazines, newspapers and internet materials. Data generated was analyzed through discourse and explanatory methods. The theory of comparative administration was adopted as a framework for the study. At the end of the study, recommendations for the effective utilization of Nigeria’s foreign policy through its economic relations instrument for garnering more foreign revenues and expanding the country’s foreign revenue sources have been proffered. Principal among which is the need for the re-direction of the attracted foreign capital to the industrial, and manufacturing sector/sub-sector of the economy where unique manufactured products in which the country has comparative competitive advantage will be sold in the international market for expanded foreign revenues.