This study investigates the complex relationship between Research and Development Intensity (R&DI) and Financial Performance (FP) within the dynamic and challenging context of Nigerian technology-intensive firms. While global literature posits a positive linkage, the unique institutional, economic, and infrastructural landscape of Nigeria suggests a more nuanced relationship. Utilizing an ex-post facto research design and a panel data regression methodology, this research analyzes a meticulously curated dataset of 9 publicly listed tech-intensive firms on the Nigerian Exchange Group (NGX) over 35 years (1991-2025). Financial Performance, measured by Return on Assets (ROA) and Tobin’s Q, is modelled against R&D, controlling for Firm Size (FS), Firm Leverage (FLEV), Growth Opportunities (GO), Firm Age (FA), Liquidity (LIQ), and Capital Intensity (CINT). The findings reveal a statistically significant inverted U-shaped relationship between R&D and FP, indicating diminishing and eventually negative returns beyond an optimal R&D investment threshold. Furthermore, firm-specific factors like size, liquidity, and leverage significantly moderate this relationship. The study contributes to the resource-based view (RBV) and dynamic capabilities theory by contextualizing them within an emerging economy framework, offering critical insights for managers on optimal R&D resource allocation and for policymakers on crafting supportive innovation ecosystems. This research fills a significant gap in the African empirical finance literature, providing actionable, evidence-based strategies for enhancing competitiveness through calibrated innovation investments.