Lean Six Sigma has emerged as a business improvement strategy worldwide, emerged from the merger of Lean philosophy and Six Sigma methodology. The literature revealed many success stories of Lean Six Sigma deployment in diverse sectors but also indicated numerous failures at different stages of deployments. Therefore, this paper mainly focuses on exploring the failure factors of Lean Six Sigma deployment and examines the most influencing failure factors of Lean Six Sigma deployment. The study's outcome underlines the eight impactful failure factors of Lean Six Sigma deployment using the Pareto analysis of twenty-eight failure factors. The literature. The study revealed the impactful failure factors as lack of top management commitment and involvement, lack of synergy of LSS and business strategy, lack of awareness on LSS, resistance related to culture change, lack of availability of resources, and lack of training and education, lack of visionary leadership, and lack of financial resources. Understanding these failure factors of Lena Six Sigma deployment may help the professionals avoid failures.