Abstract: The study aimed to investigate the key TQM factors to assure the successful implementation of TQM in the construction industry, particularly the mega building's construction firms in the Kingdom of Bahrain. This study pursues a descriptive research approach through the distribution of two questionnaires; a managerial questionnaire directed to 21 managers in these firms, while an operational questionnaire was distributed to 49 from the operational level of these firms including (engineer / technician / site inspector/ quality officer). The results revealed that there is a Significant Positive relationship between success factors (leadership, policy and strategy, continuous improvement, measurement and feedback, subcontractors and suppliers' quality management, processes management, resources management, education and training, and work environment and culture) and TQM implementation in the surveyed mega building's construction firms in the Kingdom of Bahrain. In addition, the results found that policy and strategy, continuous improvement, leadership, resources management, work environment and culture were the most influential factors that exerted a significant impact on TQM implementation in the investigated firms. The study concluded that these firms lack possessing dynamic response towards the rapid changes and instability of the business environment. Furthermore, it was concluded that these firms are relying heavily on their staff who handle their assigned tasks and also carrying on necessary improvement as per their job descriptions since there is no improvement team in the organization chart of these firms. Moreover, some of the employees do not have the expected autonomy entitled by their managers in incorporating changes in the tasks they are accomplishing. Additionally, the financial resources provided to support the improvement activities were insufficient, thus it was concluded that these budgets are set in these firms towards the accomplishment of the construction projects, while there is no finance set aside for handling any needed improvements within these projects. The study recommended to review the firms' policies to enable the proactive deal with the available resources to alleviate threats, and incorporate their decision making to address uncertainties that is implied within their dynamic business environment. Moreover, it is recommended to review the policies and practices relevant to the improvement process, and encouraging employees to have a voice in the suggestion of new ideas that might reinforce the improvement process. Additionally, to empower employees by delegating them the authority to initiate changes into their job activities for further improvements at the operational level of each department. Finally, it is recommended to assign adequate financing in terms of budget allocation to support carrying on any needed improvement to finance these needed improvements. building a quality culture is a collective responsibility of both parties. As a result of the study, a forecasting model was introduced to help the contractors to predict the level of TQM implementation to assess and improve the process to ensure the effective and successful TQM implementation.