Although supporting departments do not deal directly with the customer, they play a vital role in customer satisfaction and improve the mental image of the hotel, through its responsibility of different works with influence on the level of customer satisfaction. Since there were many supporting departments in hotels, each other provide many services that help improve performance and meet the needs of different sections because those departments are of distinct nature and structure of a special multiple acts. Hence the researchers are investigating the role of the supporting departments to improve the level of services provided in hotels and their contribution to improve the mental image of random sample of customers at five-star hotels in Alexandria. Data were analyzed using SPSS software version 20. The Findings showed that the mental image was formed among customers through many means of communication including what is personal, such as family and peer group, and what is the public as different means of media. There is a significant relation between the perceived mental image to the customers and the role of the supporting departments. It is clear that the skill level of workers alone is able to put a positive mental image of the customer about the hotel. Customers also believed that job satisfaction for workers can be seen as an indicator of improving the mental image of the hotel. Also, the results showed that the marketing and sales department, the department of public relations, and maintenance department are the important and the most influential departments in the formation of the mental image among customers. Finally, it is essential for the hotel to have a clear mechanism for workers to recognize all different departments and their concrete role in the delivery of services in the hotel. The hotel management should have a sufficient awareness that customers are able to distinguish the efforts of supporting departments. The hotel facilities work continuously on improving the mental image of hotel workers to achieve job satisfaction among workers to be able to interact with customers and change the mental image they have.