This paper explored the correlation between corporate governance and strategic performance of family-owned enterprises in Rivers State, Nigeria, and the research questions addressed the impact of the ownership structure on financial performance, the impact of the board structure on operational efficiency, the joint effect of the two governance mechanisms on strategic performance and the role of the institutional environment on the research questions. The research was done in a cross-sectional quantitative study guided by the agency and stewardship theories. SmartPLS 3.3.9 and SPSS 25.0 were applied to analyse data from 361 respondents. All hypotheses were tested successfully: the ownership structure has a huge impact on the financial performance (b=0.387, p=0.001), board structure has the impact on the operational efficiency (b=0.412, p=0.001), the combined governance mechanisms impact the strategic performance the most (b=0.461, p=0.001) explaining 44.7% The research concludes that corporate governance plays a crucial role in strategic performance in family owned businesses and suggests that the ownership systems should be formalised, boards reinforced with external knowledge, integrated governance reforms should be adopted, and succession planning should be proactive.

Keywords: Corporate Governance, Family-Owned Businesses, Ownership Structure, Board Structure, Strategic Performance, Institutional Environment, Rivers State.