This study examines the relationship between inflation and the performance of the Nigerian stock market from 1990 to 2022, using market capitalization and consumer price indices (CPIs) as key variables. Employing an ex post facto research design, this study utilizes secondary data from the Central Bank of Nigeria (CBN) Statistical Bulletin (2022) and applies multiple regression analysis using the Ordinary Least Squares (OLS) method. The findings reveal a negative correlation between inflation and market capitalization, with the results indicating that the headline CPI (HCPI), core CPI (CCPI), and food CPI (FCPI) significantly impact stock market performance. Additionally, this study identifies structural constraints, including high tax rates, insider trading concerns, and limited market depth due to the "buy and hold" strategy, which hinders stock market growth. The research underscores the necessity for policy reforms aimed at enhancing market efficiency, improving investor confidence, and ensuring macroeconomic stability. These findings contribute to the ongoing discourse on inflation’s impact on Nigeria’s financial markets and provide valuable insights for policymakers and investors in mitigating inflationary risks while fostering economic growth. Based on these findings, it is recommended that the Central Bank of Nigeria (CBN) implements policy tools to control inflation and prevent it from eroding stock gains. Additionally, the government should focus on reducing inflation and poverty through improved living standards and infrastructure development to support economic stability and market performance.