Abstract Fast Moving Consumer Goods firms (FMCG) companies are pivotal to both the economy and society, contributing substantially through job creation, tax revenue, and stimulating economic activity across their supply chains. Despite their significant role, it has been observed that these companies are facing challenges such as declining competitive advantage. These difficulties underscore the industry's ever-changing landscape, necessitating continuous adaptation to maintain competitiveness. Furthermore, integrating strong sustainability practices into their business models is becoming increasingly crucial for FMCG firms to address environmental issues, meet changing consumer demands, and secure long-term viability. The study adopted a survey research design. The target population of this study is comprised of 5,107 employees from the selected FMCG companies. A sample size of 475 was determined using advisor's sample size determination table. Data was collected using a structured and validated questionnaire with a Cronbach alpha value ranging from 0.75 to 0.85. A response rate of 93.7% was recorded. Data were analyzed using descriptive and inferential statistics at 5% significance level. The findings revealed that sustainable business practices had positive and significant effect on competitive advantage of selected FMCGs in Lagos State, Nigeria (Adj.R2= 0.610, F (4, 438) = 172.056, p<0.05). The study concluded that sustainable business practices improved the efficiency of competitive advantage of selected FMCGs in Lagos State, Nigeria. Therefore, the study recommended that management of FMCG firms should integrate sustainable practices as a core component of their overall strategy to enhance competitive advantage. KEYWORDS: Competitive advantage, Environmental sustainability, Operational sustainability, Sustainable business practices, social sustainability.