Abstract This study investigates the relationship between green practices (specifically reverse logistics and green packaging) and market share among oil and gas firms in Rivers State, Nigeria. Anchored on Institutional and Legitimacy Theory, the research explains how regulatory pressures and stakeholder expectations drive the adoption of environmentally responsible practices that enhance competitiveness. A cross-sectional survey design was employed, targeting senior staff across four oil and gas firms in Bonny. Out of 57 questionnaires distributed, 52 were retrieved and analyzed using descriptive statistics and Pearson correlation. Results revealed strong, positive, and statistically significant relationships between reverse logistics and market share and between green packaging and market share . These findings confirm that firms integrating structured waste recovery systems and sustainable packaging not only comply with environmental regulations but also strengthen legitimacy, stakeholder trust, and competitive positioning. The study concludes that green practices serve as strategic resources in the oil and gas sector and recommends systematic investment in reverse logistics and green packaging as market differentiation tools. Future research should explore regulatory moderation effects, longitudinal outcomes, and comparative analyses across other oil-producing states. Keywords: Green Packaging; Green Practices; Market Share; Oil and Gas Industry; Reverse Logistics.