Abstract: International Investment Diversification (IID) has been receiving widespread attention at both the academic and practitioner levels in recently time. Those in favor argue that international portfolio diversification is the source of an entirely different world welfare gain, distinguishable from both the gains from trade and the productivity gains from international factor movements. They argue further that there are other several potential benefits that make it attractive for investors to internationalize their portfolios. Although the implications of international diversification are well known, it is also well established in academic studies that investors consistently fail to exploit these effects, preferring to concentrate their investments in the equities of their home country, leading to what is popular known as “equity home-bias puzzle”. It is in line with this debate that this paper presents a theoretical and empirical argument in favor of the topic: Is International Investment Diversification Prudent to Either the Individual or Corporate Investor? The paper established the fact that there exist both theoretical and empirical evidence that IID is prudent to both individual or corporate investor in the form benefits such as; Risk and reward; Diversification; New market; Expertise of International Venture Capitalist; Culture integration; and Microfinance.