The economic significance and benefits of foreign trade also known as international trade to the economies of developing countries cannot be overemphasized. Its role and contributions to the gross domestic earnings, employment generation, economic development, and poverty reduction in these underdeveloped countries such as Nigeria, Ghana, Benin Republic, and others have been too glaring especially in agrarian economies with fertile arable land. The main aim of this paper was to examine in-depth the contributions and relationship between international trade and the economic development of developing African countries. Furthermore, this paper recommended stringent macroeconomic policies that when formulated would encourage and increase the multiplier effect of these (foreign) trades. Part of these policies is targeted towards exchange rates, tariffs, import and export duties, subsidies, and actions that promote international trade. The research further concluded that international trade is a key macroeconomic driver that must be encouraged in developing African countries as its multiplier effects have the potentials of driving the needed development goals of these nations. And for this to be achieved, these nations (developing countries) must formulate workable localized macroeconomic policies that suit and drive their interest as against borrowed economic policies from the developed European and Asian nations. Some of the recommendations proffered include adoption of friendly and pro-active export promotion policies, availability of grants, aids, subsidies, and loans, mechanization of the agrarian sector, adoption of flexible exchange rate, etc. This study made use of time series secondary data obtained from the World Development Indicators (WDI) and the United Nations Conference on Trade and Development (UNCTAD) of developing African countries for a period between 2000 and 2019. A forecast of 15 years was also initiated using these data to provide a long-term insight into the benefits of these trading activities on the GDP of developing countries.