Purpose: The study investigates the effect of strategic management planning on firm performance in Nigeria’s banking sector, with a focus on the moderating role of environmental uncertainty. The study aims to understand how banks allocate financial, human, and technological resources strategically and how these practices influence operational efficiency, brand reputation, and stakeholder trust under varying environmental conditions.

Methodology/Design: A quantitative research design was employed, using a structured questionnaire administered to 460 managers across selected Nigerian banks. Structural equation modeling (SEM) was applied to test the relationships between strategic management planning, environmental uncertainty, and firm performance, including the moderating effect of environmental uncertainty.

Findings: The results indicate that strategic management planning has a significant positive impact on firm performance. Environmental uncertainty also affects performance, albeit to a lesser degree. Importantly, environmental uncertainty significantly moderates the relationship between strategic management planning and performance, highlighting the need for adaptive and flexible planning in volatile environments.

Implications: The study underscores the importance of integrating dynamic capabilities into strategic planning to enhance resilience and competitiveness. Managers are encouraged to adopt flexible strategies, robust resource allocation, and continuous environmental scanning to sustain organizational performance under uncertainty.