This study will provide an overview of mental models in teams and the significance of this particular concept for design teams. Researchers have applied the concept of mental models to understand how people perform tasks on the basis of their knowledge, assumptions, predictions and expectation. An overview is also provided on the relation between performance and mental models and their effect on stakeholders. The implications for design field are discussed. Through the study of two organizations in the same industry, the teams are studied in detail for each of these companies and hence leading to the study of mental models of stakeholders. Through the use of interviews, a detailed analysis is done on the team mental models. The mental models of stack holders and their influence on different aspects of company and team performance are discussed in detail. The methodology for the study of mental models is also proposed in the study. The findings are based on the data collected through interviews in both the organizations. The empirical study is designed in such a way that it investigates further the validity of theoretical concepts. Warid is a major telecommunication brand in Pakistan that provides services in all the regions of the country. Ufone is also a well-known telecommunication brand, known for its innovative and creative TVCs (TV commercial). Interviews with the marketing and sales officials of both these organizations provided an insight into the teams behind their advertising/marketing campaigns and the affect of stakeholders’ mental models on the performance and sales of the companies. The comparative analysis between the theoretical and empirical studies suggests that the quality of mental models is affected by diversity in the team, education and experience of the team members. This may be brought in for future research to further verify the effectiveness of mental models for design teams and eventually the whole organization. Finally the implications of our findings are discussed.