This report provides a comprehensive analysis of team effectiveness within Walmart, drawing on group theory to critically examine the factors influencing team performance. The report begins with an overview of Walmart's history and evolution, highlighting its strategies for employee management and retention. It then delves into the concept of team effectiveness, discussing its importance and the key components that contribute to successful teamwork. The report identifies challenges Walmart faces regarding team effectiveness, such as trust issues, lack of open communication, and difficulties in decision-making. Various models of team effectiveness are explored, including the GRPI Model, Katzenbach and Smith Model, T7 Model, LaFasto and Larson Model, Hackman Model, and Lencioni Model, to provide a theoretical framework for understanding the issues. Finally, the report offers recommendations for Walmart to enhance team effectiveness, focusing on characterizing and communicating vision, energizing recognition, fostering open communication, empowering employees, and promoting continuous education. The report integrates relevant theory with organizational data and examples to provide a nuanced understanding of team dynamics within Walmart.