The focus of the study was on examining International Financial Reporting Standard (IFRS) Adoption and The Value Relevance of Accounting Information in Selected Africa Countries: A Comparative Analysis of Nigeria and South Africa. The focus on cross country analysis in the subject of IFRS adoption and value relevance is growing quite slowly. However. Cross country empirical studies for countries in Africa continent is largely non-existent or at best difficult to find. This study address this gap by adopting a cross-country approach using Nigeria and South Africa. The study employed a longitudinal research design. The population and the sample of the study comprised the top companies in each country by way of market capitalization for the countries in the study, namely: Nigeria and South Africa as at December, 2019. The convenience sampling technique was used in the study to select listed firms across the two countries. Secondary data sourced from corporate annual reports of the sampled quoted firms got from the Nigerian Exchange Group (NGX) and Johannesburg Stock Exchange (JSE) were used for the study. The study made use of panel data regression and the results revealed that for South-Africa, Earnings Per Share (EPS) and EPS*IFRS were both positive respectively, and also statistically significant. Book Value Per Share (BVPS) and BVPS*IFRS were both positive respectively, and also statistically significant. Dividends Per Share (DPS) and DPS*IFRS were both positive respectively, and were also statistically significant. Intangible Assets (INTA) was not value relevant in the pre-IFRS period given the absence of the statistical significance of the variable, but show some evidence of weak incremental relevance from IFRS adoption as the interaction between INTA*IFRS was significant. Cash Flow Per Share (CFPS) was positive and significant; and furthermore, the interaction of CFPS*IFRS was also positive and statistically significant. For Nigeria, EPS and EPS*IFRS are both positive respectively, with EPS statistically significant. BVPS and BVPS*IFRS are both positive respectively, with only BVPS statistically significant. Furthermore, DPS and DPS*IFRS are both positive respectively, and statistically significant. INTA and INTA*IFRS are both insignificant respectively. Finally, CFPS is positive, though not significant; but the interaction of CFPS*IFRS is positive and significant. It therefore implies that, EPS*IFRS, BVPS*IFRS, DPS*IFRS, INTA*IFRS, CFPS*IFRS shows whether EPS, BVPS, DPS, INTA, CFPS reflects a stronger statistical significance in explaining share price when interacted with IFRS adoption (post) than without it (pre) in the two selected Countries( Nigeria and South Africa) . The study concluded that, there is the need for capital markets in developing countries to become more efficient and for companies and accounting regulatory institutions to ensure timely and quality disclosures of accounting information. It recommended that stock exchanges in developing markets should put a frame-work in place that measure the rate of compliance of each listed firm’s annual report with IFRS demands to enable the sanctioning of firms that recorded below the expected compliance level. The study also recommended amongst others, that financial reporting councils and accounting standards setting bodies globally should support the effort to ensure improved compliance with IFRS as a matter of policy.